Remember that you're not the first to think of such a trip -- you'll be with alot of peiple you've never met. Travel along Route 1 in Maine is slow at the best of times -- especially Ogunquit (I wouldn't even get on Route 1 until Wells), Wiscasset, and Camden. You will not get through these quickly. It's a fact of life so get used to it. Our motto "Life in the slow lane" is especially true for Route 1.
August is prime time -- start making your reservations now. If you don't have kids who have to be in school, think about September -- still great weather with fewer people. Nothing closes up until mid-October.