Plenty of stuff in New England to see and do. Picking one place out of the whole US to see is just as daft as American tourists coming to ‘do’ the whole of Europe in a week.
Motorhome touring is hideously expensive. Best way to tour Imo is to buy or bring a small tent and camp at state or national parks. You get a little table and campfire in the woods, it’s the best place to be in the evening. Not like UK camping really. And cheap too.
Buy the rough guide to the usa. Good writing and they manage to inspire the reader to want to see and understand every region rather than just make a beeline for the crowded tourist spots.