Although there might be old lumber available in Oswego I would not count on it. It's much better to make your own before you get there. Make a crutch for the mast out of plywood for the pushpit. It should be fastened to 2x4's and bolted to the sternrail with U bolts. Make a sawhorse for the mast to sit on at the bow. Also one more support at the mast step/partners. Make it high enough so that the mast can fit over the dodger because sure as hell it's going to rain on the trip through the canal. Take plenty of lines
for lashing as you will be waked both in the canal and on the Hudson. You have to cross Lake Oneida and it can kick up pretty fast on that shallow lake. Put the mast on deck butt end forward. This is in case you touch the side of a lock when entering. Doesn't hurt to put a small fender
on the mast/furler.
When you are doing the mast in Oswego here's a few tips. Keep the headsail on the foil and lash the whole works to the mast. Keep the main on the boom and stow on deck. This way you protect the foil and also don't have to store sails down below.
The only place for doing the mast in Oswego is Oswego marina and they are a pretty good bunch there. When you get to the Hudson the best spot to step the mast is Riverview Marina in Catskill. Mike, the owner is very helpful.