my 2 cents:
Since this is your visit, make reservations (early) with the Acadia National Park Campground. There's a very good intrapark transit system that goes to a lot of places, including stops in 'downtown' Bar Harbor. The trams were free two years ago and we're really handy/timely.
Plus by staying in the park, you can get the newsletter which shows all kinds of things to see and do... very helpful, very cheap (no charge or low-cost "tours"), and fun!
Certainly a toad is nice and it gives you more flexibility, but I sure wouldn't think of it as a requirement, especially in this park. Things are set up very well at Acadia to handle your transportation needs without having your own car. Bike rentals are easy too.
Last Brave 2004 34D