Fall colors in upstate New York

I assume you're splitting this up over a few days. If you're thinking this is a full day of driving, well, it'll be a very full day.

I'm not familiar with those particular roads through the Adirondacks; they might have some steep grades and sharp curves (or not). It looks like you're actually planning on NY 3 from the Watertown area to NY 86 to NY 73 to NY 9N (south). Once across the bridge, the roads you're taking should be just fine for your RV. (I might suggest taking I-89 rather than US-2 as shown between the Burlington area and Montpelier. The two roads are equally as scenic--often within sight of each other--and the interstate is easier driving and generally in a bit better shape, though US 2 isn't terrible.)

In late September, particularly in the area around Lake Champlain, you're likely to be a little early for too much color on the trees. Getting into the Northeast Kingdom and White Mountains there will probably be a little more. Of course, it does vary from year to year anyhow. The traditional peak of foliage season in Vermont--at least in terms of leaf peepers out and about and clogging up the roads--is Columbus Day weekend.

You may wish to consider taking US 2 all the way from Rouses Point, NY (at the northern end of Lake Champlain) and down through the lake Champlain islands. You also might want to look into taking the ferry across the lake. (Driving between Burlington and Plattsburg, the northern route via Rouses Point is about 20 miles shorter than the southern route via Crown Point...and the ferry of course quicker and shorter than either.)

The prettiest route is Route. is from Binghamton to Albany Via I-88 or if you have time Route 10 thru Delaware county.

Wildwood CG in NH is a typical small NFS primitive CG. No hookups, no flush toilets, and very small. Not sure your 5th Wheel would even fit in the CG or in the campsites. The last time we were there we camped in a tent and were driving an MG Roadster - even then it was small. There are several nice private Campgrounds in the area, but at foliage time they will be very busy.