made subsequent to submission of the report:
Middlesex Avenue in Natick does not exist west of Union Street and therefore can not serve as an alternate to Route 135.
An alternate route to Hartford Street in Natick is via C street or Howe Street, Framingham to Brookdale Road, Boden Lane, and Burning Tree Road to Mill Street. Crossing Mill Street, Beaver Dam Road may (should) connect with Edwards Road to Speen Street. Hartford Street should get a purple and orange rating -- it carries heavy traffic in rush hour and is not very wide.
The east end of Bacon Street in Natick has houses along its north side between it and Morse Pond. Therefore, any bicycle path around the south end of the pond would have to go up on the railroad right of way, across the railroad bridge over Bacon Street, and down to Bacon Street on the south side. This could also have the advantage of avoiding the first block of Bacon Street, which is narrow.
While many people are studying the connection from Riverside Station into Newton Lower Falls on an unused railroad right-of-way, another possible connection is by crossing the Charles River to Recreation Road. A Turnpike frontage road already crosses the river here and it would not be difficult or expensive to cantilever a bicycle and pedestrian bridge off the existing bridge. This would offer a direct, short (walking distance) connection between Riverside Station and the Leo Martin golf course and cross country ski track.