Based on your itinerary, my specific recommendations would be to drive the Kangamangus Highway when you're up in North Conway and maybe head over to the Mount Washington Hotel for a drink or lunch. In Boston, be sure to do the duck tour with some clam chowder from Legal Seafood (in the Pru, near when you cathc the duck tour). If not the duck tour then at least a walking tour of the Freedom Trail.

Portland for only 1/2 day (Old Port and Portland Head Light), up to Camden, then Bar Harbor and Acadia National Park. I can't imagine coming to Maine without visiting Acadia. If you do go to Ogunquit, be sure to walk the Marginal Way and visit Perkins Cove.

Try Camden Maine. It's spectacular bay and easy going town is a great example of coastal NE without the hype. Stay at a B&B. Maybe the Captain Swift Inn.