Maybe go online and take a look at back issues of The New England Hockey Journal - I believe they run a prep 'primer' sometime in the spring or early summer. Heck, contact them directly and they can help you at least get a start geographically. Or look up New England Prep / Hockey on Wikipedia and at least you'll get listing of locations.
NEHJ only profiles schools that buy ad space. It's far from complete.
You can find a list of schools with active links to the school websites on NEPSAC.org. Unfortunately,m that may mean a lot of click-throughs to find those in your area. But, it is comprehensive.
The best hockey schools are the Keller Division ISL schools. Not much of a chance for a developing kid to crack their lineups, and don't expect you can make it form JV - they recruit internationally.
Eberhart Division schools are supposedly academics first, but even there, it's changing. You could look at St. George's in Newport, not sure if that's commutable.
The other school I'm familiar with down that way is Tabor Academy. Not sure how good their hockey team is.
Tabor has a very good program, definitely the best in the RI, southeastern Mass area.
Sounds like you live in RI so there is not much to choose from within a short driving distance. If boarding is an option then Tabor is fine but if again, if boarding is an option then you should consider all boarding options around New England and there are many.
If your kid drives and you don't mind him making a long commute then there are a number of day schools along the 128 stretch from South of Boston to I90 but it all depends on where you live to know if its feasible.