If you're planning on doing this, I'd say start in Lockport instead of the actual beginning in Tonawanda, only because parking your car for a couple days in Lockport will probably be easier. Heading east the trail is all nice west of Rochester with maybe a 10 ft gradient the entire time. The best places to turn off heading east from Buffalo for food, shelter, etc would be Lockport, Medina, Brockport, Spencerport, Fairport, Palmyra, Newark, Lyons, Seneca falls, Port Byron, Weedsport, Syracuse, then into your neck of the woods.
Also NY just put on some kind of big cycle tour last week, you can check out ptny.org, it has maps of the entire canal an gives mile by mile altitude etc (
https://www.ptny.org/cycle-the-erie-canal)
Oh and I ride 32mm with no real problems up there on the gravel(gatorskins and armadillo elites, one ride for 74 mi w/ gp4000 all seasons). plus more stores have 32's in stock up here if you have a blow out, whereas people might not have 35's or 37s.