This will come off negatively, so I apologize in advance...
1. Make sure you have deep pockets, or at least a LARGE initial investment. Doing business in the northeast, especially Massachusetts, is full of ridiculous amounts of expense and red tape. As with starting any business, don't expect to make any money for a couple of years.
2. Overhead will kill you.
3. Do you have any real-world practical mechanical or fabrication experience? Welding, setting up diffs, designing suspension? Do you own any tools? Certificates, diplomas, and education are one thing...years of experience and a reputation will get you farther in the long run. And even that won't ensure success. (Look at Domenic's Auto and Jeep as a prime example. People ****ing LOVED that guy, everybody got there stuff worked on by him, he had an excellent reputation, and he still went out of business.)
4. There is no money in parts, unless you are selling A LOT of parts.
5. Ditto on this community being cheap ****s. Every DIY'er or know-it-all thinks he can do it better or cheaper than you.
6. Be willing and able to work ALL the time.
Do I sound bitter? I have first hand knowlege of opening an off-road shop in New England. I also have first hand knowlege of having to close an off-road shop in New England...why? See 2 and 6 above. It sounds awesome in theory...it is most assuredly not.