Route from Bar Harbor, Maine to Essex Junction, Vt

We have used I95/US2/I93/I89 pulling two different 5ers, a 35 footer and a 38 footer. Route 2 has a fair number of hills and of course traffic that can only be classed as trying to your patience but usually not too heavy. We do it in a day, but your idea of an overnight would work well though I can't recommend any CG, but would look near Gorham, NH and consider a side trip to the Mt Washington, NH area if you have the time.