You don't have to go far, Watertown, MA offers many walking paths and connections to popular destinations.
Watertown Linear Park
0.2 Miles of Public Trails
https://www.mass-trails.org/towns/Watertown/linearpark.html
Watertown Riverfront Park & Braille Trail
0.5 Miles
From Watertown Square to Brighton, this "braille trail" was created for the blind and blind deaf to enjoy nature.
https://explorethecharles.com/2019/01/06/watertown-riverfront-park-and-braille-trail/
Charles River Greenway Bridge
2.3 Miles
https://myhikes.org/trails/charles-river-greenway-trail
Charles River Reservation
Over 20 miles of trails are available for biking, walking and running.
https://www.mass.gov/locations/charles-river-reservation
Explore All Trails in Watertown, MA
http://masstrails.com/watertown.html