Following the
Seaway Trail along Lake Ontario is an interesting way to cross NY. There are many state parks along the trail, many on the lake that are good overnight stops. One of my favorites is a bit south of the trail, but well worth a stop -
Letchworth State Park. Three beautiful waterfalls; the park is often sited as NY's finest. If you take the Seaway Trail, wave as you pass through Oswego!
US 11 is the fastest 2 lane across northern NY, but NY 3 through the Adirondacks is more interesting. A bit windy, but a pretty drive. As a side trip, the
Adirondack Museum is worth a stop. Taking either US 11 or NY 3, you will pick up US 2 as you cross into Vermont.
I've taken US 2 all the way to
Lamoine State Park in Maine (just outside Acadia National Park). Lots of small towns & villages; you won't make great time like you would on the interstates, but it is a lot more enjoyable.
For a different route back, I've taken US 20 across MA & NY. Again, lots of small hills & small towns, but more interesting than the MA Turnpike & NY Thruway, which parallels it.