Hi Mark, I've been up the Maine coast a few times (from Boston), below are some thoughts that may help you plan your trip.
* Of all the beautiful destinations in Maine, Bar Harbor was not on my top-20 list. I'd recommend investing in a cruising guide:
A Cruising Guide to the Maine Coast: the definitive reference for exploring the Maine coast by boat.
www.mainecoastguide.com
* The season turns early up in Maine: I remember seeing my breath in the air, in early September, and it can get rather foggy. Watch the hurricane season, it can ruin any cruising plans / schedule.
* Sailing "down" (the wind) to Maine is generally a pleasant run, with the prevailing south-westerly winds; Coming back home ("up" - against the prevailing winds) can be tedious beating. I'd recommend you go fast to your final/furthest point, then slowly work your way back respecting the weather / conditions. Ten days is not a long time, and the coast has so much to offer.
* Lots and lots of lobster traps, which are a magnet for fin keels, spade rudders and exposed props. Very (!!) tedious, and potentially dangerous if you get hung up at night. The ocean is chilly - I used to carry a neoprene suit for going overboard.
* From RI, you may want to time your passage through the Cape Cod Canal, and stop at Provincetown. Straight jump to Monhegan Island (or Matinicus), or via Isles of Shoals (off Portsmouth NH). After Monhegan, jump to Frenchboro, then Bar Harbor. On the way back home you may want to hug the coast (lobster traps!) and stop more frequently.
YMMV of course, and I'm sure there will be more good thoughts on this thread ... good luck and enjoy Maine!
Zoran