A Short Walk along the water? Long hike through the woods?

Crystal Springs - located across from the Dunkin on Fellsway, take this trail up to the 

Virginia Wood Loop - parking on Pond Road for 4-5 cars.  You can also walk from Crystal Springs, but be aware that the trail is a little hilly and you need to cross Ravine Road. 

Bellevue Pond - off S. Border road in Medford, a few parking spaces and trails that go around the pond. 

https://www.mass.gov/doc/middlesex-fells-reservation-trail-map/download

Greenwood Park -  located across from the zoo, which also has a great playground, field and plenty of parking. Lots of easy trails with gentle hills. Most are OK if you have a trail stroller, but on foot is best. 

Sheepfold - from the paring lot there are a bunch of different trails. There is a large open field near the parking lot where dogs play off leash, beware of pups and poops. The trails are pretty well mapped, they're not stroller friendly.  

https://www.friendsofthefells.org

This trail is mostly open but follows a 2 mile loop from the top of the pond around the park there are some covered areas. You can see frogs, birds and sometimes fish at the pond. If you follow the trail to the right after the parking lot you end up at a large play area: swings, climbing structures, soccer fields, a paved loop around the field which is great for bikes and strollers as its mostly flat. There are also picnic areas and basketball courts. www.ipswichriverpark.org/

This almost entire flat paved loop runs around the entire lake. I find parking easiest at the bottom of the lake at the church lot and then follow the lake towards Reading. There are playgrounds at the top and bottom of the lake. Off North Ave there are new pickle ball courts, tennis courts and baseball fields. https://folq.org

If you follow the road behind the high school there is a good amount of parking near the Voc school. Enter the trailhead and turn left, the main trails are paved, follow for about 1 mile and you come to a scenic pond, a playground, picnic areas and a sandy beach. off the paved trail you'll find lots of wooded trails all pretty moderate. This has some very small hills. As you pass the playground the hills get much steeper. https://www.mass.gov/doc/breakheart-trail-map/download

If you follow the road behind the high school there is a good amount of parking near the Voc school. Enter the trailhead and turn left, the main trails are paved, follow for about 1 mile and you come to a scenic pond, a playground, picnic areas and a sandy beach. off the paved trail you'll find lots of wooded trails all pretty moderate. This has some very small hills. As you pass the playground the hills get much steeper.

Located on the Melrose/Malden line, Pine Banks park offers paved trails, wooded and hilly  trails, playground area, picnic, ponds, playing fields and a track.  Park off Main Street and take the Cray Trail up to Mt. Ephraim for views. https://www.pinebanks.org

This hidden spot is technically in Stoneham. It's moderately hilly, nice wide paths through the woods, that are pretty well marked. Some of them are easier than others and I have seen moms with strollers (like a Bob/Mountain Buggy). There are mostly smooth trails with the occasional rock or root. Easy, plenty of parking.

This paved and slightly hilly spot offers great views of the Boston Harbor and skyline. There are only about 20 parking spaces, but there is also an MBTA stop. There is a pier, lots of benches to sit and of course, the sewage waste tanks...the inner loop is a little hilly. https://www.bostonharborislands.org/deer-island/

Head through Southie and park at Castle Island. For a longer walk, park at the Pleasure bay flag pole just off Day BlVD . Walk around the fort and bay, enjoy the playground, sailing pavilion, ice cream/burger shack and you can watch the ships and planes from infant of Fort Independence. https://www.castleisland8.com

This trail follows the beach, through a butterfly garden, marshy trails and out to Fort  Ruckman and Bailey Hill. Not stroller friendly, but fairly easy

https://nahant.org/recreation/heritage-trail/

This paved trail follows the beach from Lynn to Swampscott. Not much shade, but easy for strollers. There are a few benches, parks and playgrounds along the way. Plus you can watch the planes landing. 

https://nahant.org/recreation/heritage-trail/

Parking lots at both the DCR headquarters and Spot Pond Boathouse lead to trails all along the pond. You can follow the length of the pond into Medford. And although the paths are not paved, the dirt is hard packed and you can easily push a stroller.  It's scenic in that it runs through the woods, and offers quiet views at the pond. There are also picnic table at the Community Boating Launch and a flat grassy area for kids to run.

There is lots to see here, you could take two trips and not see it all. The paths are well maintained, there are fun stone bridges, rock formations ("The Rockery") and many wooden plank paths through the woods.  Ample parking and free for Audubon members. It does get hot, not really a stroller friendly spot because of the hills and roots. https://www.massaudubon.org/get-outdoors/wildlife-sanctuaries/ipswich-river

A gem!  This working farm has lots of animals to see, well maintained paths, museums and picnic spots. Wildlife exhibits, activities, farm stand and more. It's hilly but it is stroller friendly.   Another Audobon property, but open to the public for a fee.https://www.massaudubon.org/get-outdoors/wildlife-sanctuaries/drumlin-farm

A former estate, this spot features 721-acres of pine needled paths, rolling meadows for hiking, biking, and a splash pad and playground. https://www.ectaonline.org/trails/bradley-palmer-state-park/

Gentle trails through the forests, across meadows, and around ponds and vernal pools. You're definitely going to spot some wildlife along the way.    www.massaudubon.org/get-outdoors/wildlife-sanctuaries/habitat/bout 

There are dozens of trails an dover 700 acres to explore. This is a Trustees property and conservation land that winds around hills and through swamps. Most of the trails are fairly easy, unless you take the Blue trail to the summit of Boston Hill for the views, this isn't  stroller friendly. https://www.fonat.org/ward

Explore the park's trails,  tide pools, rocky ledges, and learn about the park's World-War II history. You can follow it up with  lunch at the Lobster Pool

https://www.halibutpointfriends.org

Crowninsheild Island ( Browns Island) is only accessible by boat or walking during low tide. There is a beach nearby known as Grace Oliver's (shallow, rocky inlet great for little ones). Street parking is only along the beach road which is difficult and narrow.

This is such a beautiful property and a great place to let the kids run! There are beautiful gardens, rolling hills, the old estate and views out to the beach/ocean. There are also a few farms nearby, depending on the time of year you can pick up local apples, cider donuts or fresh berries. I have seen people use strollers but I wouldn't say it's super stroller friendly. Advance passes are suggested, not required. https://thetrustees.org/place/castle-hill-on-the-crane-estate/

Trails run along Indian Brook and the Charles River and have lots of wildlife: dragonflies, turtles and more than 175 species of birds. The trails are really well maintained and pretty easy to navigate - some in fields some shaded in the woods and along ponds.www.massaudubon.org/get-outdoors/wildlife-sanctuaries/broadmoor

Plan ahead because you could spend a few hours here -   swimming, walking around the famous pond and through the woods, picnic spots,  boating and the replica of Thoreau's cabin. Check for hours and be aware there might be goose poo around the pond. There are parking passes available on the state site:

https://www.mass.gov/locations/walden-pond-state-reservation

Walk along the beach and collect rocks and shells, or visit the "sandy" section. There are also fort remnants to see and a  lighthouse. There are short trails and the entire place can be walked in about 20 min, keep that in mind unless you plan to hang out at the beach. Fee for parking. 

This is a 25-mile route of the old New Haven Railroad Framingham & Lowell line. The trail has a 10-foot wide pavement with a 2-foot wide packed shoulder on each side. You can enter this trail from a number of different locations, parking lots and playgrounds are scattered throughout the trail access points. .https://brucefreemanrailtrail.org

Beautiful trails through a 45-acre home to the New England Wildflower Society and one of the best places to see over 1000 varieties of wildflowers. The main trail is nice and compact and stroller friendly, the off-shoots are a little hilly and have stone staircases. There are plenty of spots to take a break and rocks, adventure playscape and stegosaurus statue. 

https://www.nativeplanttrust.org/visit/garden-woods/

There are over 16 miles of trails to hike through beautiful gardens, rolling meadows, huge pine trees and along the Merrimack River. There are some paved and unpaved trails, restrooms, old historic buildings and its all well marked. https://www.maudslayassociation.org/trail-maphttps://www.mass.gov/locations/maudslay-state-park

Hike through 20 miles of protected forests, fields, and wetlands and vernal pools,  and the red maple swamp boardwalk.  There is a Cookie’s Garden, a Nature Play Area with room to climb, explore, and create your own rhythm on naturally-made musical instruments.The Farm at Moose Hill: offers  a CSA and organic local veggies.

https://www.massaudubon.org/get-outdoors/wildlife-sanctuaries/moose-hill

www.lexingtonma.gov/DocumentCenter/View/408/Trail-Guide-PDF?

Large wooded park with with significant wetlands, groomed trails, cinder paths, and dirt roads. It's all relatively flat, runs through the woods between Waltham and Lexington, Brook North Reservation covers 254 acres. From the top of Mackerel Hill, views of Boston and the Blue Hills can be seen. Mostly stroller friendly, especially on the carriage roads.

https://www.lexingtonma.gov/DocumentCenter/View/408/Trail-Guide-PDF?bidId=