Lifetime New Englander (Mass) new to FMCA and RV'ing this year. So these recommendations aren't necessarily from a RV'ing perspective. In Maine: Acadia, Rangeley, Sebago Lake (Point Sebago CG), Rockport, Bar Harbor are some of my favorite areas and you could easily spend a week in each and still not see all there is to see. New Hampshire: Franconia to Lincolin, N. Conway (lots of tourists & shopping), Lake winnipesaukee. Massachusetts: Lots to see in Western Mass and along the Mohawk Trail, Lots of neat places on the North Shore but traffic and roads must be checked carefully (low bridges and narrow twisting conditions) South Shore - Plymouth, Cape Cod, and the South Coast are worth the detour from route 95 (avoid traveling to the cape on any summer Friday afternoon/early evening at all costs). Don't forget RI with Newport and all the mansions and stunning coastline and beaches.
That will easily fill your 8 weeks.
Good Luck
FYI - I'll be going the opposite direction in May to Charleston SC.