Lots of places to stop, but they're often a ways in from the ocean. How much time do you want to spend going up & down fingers? April and May are likely to be quite cold and foggy. Are you wanting to stop a lot or do you just want to get to Boston? From Bar Harbor, Stonington might be a good initial run, to make sure all your systems are working properly. Billings in Stonington can fix just about anything that needs fixing. From there, Portland might make the most sense, unless you want to check out Camden, Rockport or Rockland. We did not like the reception we got in Vinalhaven - silence and cold stares when we inquired about moorings - the only unfriendly place we've been in Maine. Unless you want to try Portsmouth NH, it makes sense to head for Cape Anne after Portland. Marblehead, Gloucester, Manchester and Salem offer quite different experiences. Rockport, MA is nice too, but quite touristy. Tell us more about how much time you have and what interests you. Taft's Cruising Guide to the Maine Coast should be in your library and on board for the trip.