There'll be no direct / off-road / trail link, I'd guess. Though there is pavement from Putnam Av to where the Putnam line's tracks end in the Metro North yard, I doubt that'll ever be open to the public. Notionally, continuing through the yard and crossing the tracks on Prospect Hill Rd is just that: notional.

Clarified in your subsequent reply, the stub / access point (shown on Open Street Map) east from North Main Street to the Maybrook Trail

https://www.openstreetmap.org/#map=16/41.4025/-73.6195&layers=C

between Brewster and Southeast is consistent with what the trail brochure from June 2013 labels "To Putnam Trailway".

(And BTW, thanks for posting the link to the June 2019 brochure!)