I've been to Boothbay, some cool shops, but only been thru Camden and Rockport.
Old Orchard was nice in the summer months but I'm just looking for the first night to have a stroll along the beach looking for Sand Dollars and enjoying the ocean breeze. It'll be chilly, but Old Orchard was more 'for the kids' when I visited there. It has a few shops and a pier, but the tide there was the most memorable thing. Watching the beach grow about half a mile (well, it seemed that way) out was very cool.
The rocky coast offers a ton of tide pools to discover sea life at your fingertips. It will be fun to pick up crabs and watch the wife squirm as she trys to catch one. The Lobster Dinners with a bottle of Wine will be great as well. I can't wait!
I'll contact you later this year when it gets closer to the time we are heading up there. I could always use a few tips from a local on what to do