Kancamagus highway in New Hampshire is a must see.
Do not drive into Bar Harbor with any kind of large RV.
Traffic can be extreme along the coast Friday and Sunday.
Be an early riser to drive in Acadia. After about 9, traffic gets heavier and it’s hard to park in the more popular attractions. Bus is free and well worth it after mid-morning. If you are up for a hike, the trail to the top of Cadillac Mountain is an accomplishment. Sunrise at the top is worth the early start. You can drive to the top if you prefer.