Best routes for driving in an RV?

This California girl has always wanted to see the beauty of the Adirondacks, but now that we live full time on the road we've left our tent camping for an older 32' Motorhome with tow dolly and car. I'm trying to plan our route from Alexandria Bay region down through the park to Saratoga Springs, with no rush or hurry, just time to enjoy as much as we can and I need any help I can get. And, we don't like using interstates if at all possible. Problem is the RV is older and doesn't like climbing mountains. Are there any roads that would be better than others as far as few high elevation drives, or is that even possible. Looking at the maps I was thinking of Cranberry or Tupper Lake on highway 3 with day trip to Lake Placid, since everyone says that's a must see. Then south on 30 to Blue Mountain before continuing on. I'd like to stay about a week at a time in a campground and do day trips rather than driving all over in the RV. We have our kayak to enjoy the lakes and want time for hiking. Thanks for an advice, and BTW we love upstate NY! What a gorgeous part of the country this is.