Check height and draft requirements for the canals. 1st half or Erie to Oswego and Oswego canals are OK with probably 22 ft. air draft, second half of Erie is low.
Fun things when we were there included:
Stop on Hudson River and rent a car at Catskill, NY Marina to tour the beautiful area. We stayed there 3 days to see Hyde Park (Roosevelt homes and FDR library), the Vanderbuilt mansion, the Rockefeller mansion, and I loved the Rhinebeck Aerodrome. It's an operating antique airplane museum and flying field, whith some great old planes and engines on display. Unbelievably, they still fly some of these planes that are more than 50 years old.
Stop at Brewerton, NY and rent a car to go see the Corning, NY Glass Museum and stop on the way back at Taughannock Falls state park to see the high falls (small but higher than Niagra Falls and a nice trail through the park to get to it). Can also stop at Canandaigua, NY to see the Sonnenberg Mansion and see some of the Finnger Lakes area.
Stay at the long free dock in Waterford, NY at the start of the Erie Canal. Very nice and welcoming to cruisers. You can go for a walk along the old original Champlain canal segment there to see the original teeny, shallow mule power canals of the 19th century.
Oswego Canal, stop for lunch at the free dock of the teeny town of Phoenix, NY where the "Bridgehouse Brats", school kids on vacation, will bike for a few bucks tip to get you pizza or sandwiches from the local stores. Dock at the free dock at the end of Oswego Canal right before the last lock to Lake Ontario. You can walk over to see Fort Oswego from there too.
Definitely go up the St. Lawrence River through the 10,000 Islands area. It's beautiful cruising country.
In Rome, NY, there's a free dock that's just a wide spot in the Erie Canal with a nice, straight dock to tie up. It's a free public dock, but there's no electric or water available. There are lots of stores, an old fort and a restaurant in walking distance and a good restaurant that provides free rides if you call them.
Sacketts Harbor, NY on Lake Ontario if fine for overnight at the marina, but Ho-Hum, as is Clayton, NY just up the St. Lawrence.
If you go to the Canadian side of Lake Ontario, Kingston is a cruiser's dream. It's right at the start of the Rideau Canal. Plan on staying there a few days. They have a beautiful marina, right downtown, the farmer's market, free concerts, antique shows, lots of tourist things, take a cab to Fort Henry (magnificent and not to be missed including marching demos and firing the old canons). The fort guards the entrance to the Rideau Canal at the confluence of the canal, the St. Lawrence Seaway and Lake Ontario. Kingston also has lots of shops and stores, horse drawn carriage tours of the city, etc.
Have Fun!
Doug