Rental car? You won't absolutely NEED it, but it will sure make your visit a lot more enjoyable. Rockport is actually a tiny village, and while very pretty for the first day or two you'll soon want to go to Camden (definitely too far to walk), Rockland, etc, as long as you're there. It's worth taking an extra day or two to visit Arcadia National Park (photographically stunning). My experience with a George Tice workshop was excellent. I've also been back to visit for lectures and the bookstore several times while working up the coast.