Same sort of question for another short trip I'd like to do. Leaving from Newburyport, head out the mouth and turn south along plum island, circumvent Cape Ann, and come back through Plum Island sound. That's about 53 miles, be a cool day trip.
Pick up a copy of Marine Yellow pages/ Atlantic States. At boat shows or dealers. Also at www.marineyellowpages.com
Everything you want to know there. That's the commercial Marine Industry guide to the products and services in the Atlantic States.