N. Ga to Bar Harbor

I-81 to either I-84 or I-88 as preferred to I-90 to I-495 around Boston to I-95 is what I'd do. To get to I-81, it looks lik US64 to either I-75 or I-26 would be reasonable, and offhand I can't see much to prefer one over the other.

If time is plentiful and you don't mind hilly, curvy, slow going--but beautiful and peaceful--roads, the Blue Ridge Parkway (and perhaps continuing on Skyline Drive through Shenandoah National Park) may be an option. Do plan ahead regarding tunnel clearances as needed.