I would go directly to Eastern Bay from SW Harbor or from Little Cranberry skipping Bar Harbor as SG suggests, to spend more time in that area. If you and your wife enjoy hiking be sure to tuck into the Mudhole at Great Wass Island and enjoy the Nature Conservancy trails ashore. The photo is from the eastern end of the island looking toward Mistake I. I would probably skip Blue Hill Bay to spend more time in Penobscot Bay and the area around Isle au Haut. By mid-August it gets pretty busy with vacationing cruisers but you should have your pick of anchorages during your time frame. On your trip south you might consider a stop at Isles of Shoals unless you have a strong desire to see Portsmouth. It's not a bad run from Casco Bay and an easy day from there to Gloucester or points south.