For the best in the Mt. Dessert through Penobscot Bay, I'd spend a couple days sailing and overnighting through the Merchant Islands and the Fox Island Thoroughfare. Many anchorages to pick from and a few rental mooring options. Good in any wind. (Anchorage off Hells Half Acre. Moorings in the Thoroughfare: Browns Boatyard in North Haven, Perry Creek has private moorings but they are used by transient boats).
In the middle, Tenants Harbor has protected moorings, great food at Luke's Lobster (opens tomorrow) and this is a good spot to push off out of the bay and head Southward.
Weather will then become the greatest factor in your timing when you leave Penobscot Bay. Boothbay is a convenient spot to overnight, moorings and protected anchorage.
Casco Bay has several good island anchorages in the outer bay, pretty and convenient(Jewel is a good one).
Biddeford Pool is a great stop, moorings and anchoring options.
Isle of Shoals is a great overnight. You can usually pick up a vacant mooring but odds are better during the week. You're 10 miles off Portsmouth.
That's only scratching the surface but will use up 10 days .
Midcoast Maine provides the most options for a 10 day itinerary. Use Rockland as your 'base' for supplies and head across towards Vinalhaven and surrounds. Pulpit Harbor, Seal Bay, Merchants Row, Eggemoggin Reach, Castine, Blue Hill Bay (to gain respite from the lobster buoys, but not necessarily Blue Hill itself) Southwest /Northeast Harbor, and perhaps down towards Pemaquid all offer the 'Maine experience'. 10 days only scratches the surface...