Congratulations on selecting one of the best made Jeeps for offroad. Above, Bob has given you the best possible advice. There is a lot to learn about your Jeep and four wheeling in the wilderness. The quickest way to learn about Jeeps and four wheeling is to hookup with other Jeep owners and go on a few trail rides. There are many advantages to cultivating a few knowledgeable Jeep buddies.
Keep in mind that building your Jeep for offroad excursions will reduce the Jeep's street-abilities. From what I've read of the New England Region, access to wilderness areas are extremely limited. It appears that unless you can travel a few hours into Maine, there really isn't any real good reason to modify your Jeep to fit 33" tires under it.

Your particular Jeep came equipped with many offroad advantages that earlier Jeep owners paid big dollars and a lot of time to have; specifically, the Dana 44 rear axle with the limited slip differential. True, the Unlimited's breakover angle will get you hung up more frequently offroad than the Wrangler Sport unless you increase the Unlimited's ground clearance; but the rear cargo area is that of the Cherokee's.
If you do decide to modify your Unlimited after four wheeling with other Jeep owners for an extended time, I would recommend visiting several 4x4 shops where at least some of the certified mechanics are Jeep enthusiasts and are actively involved in four wheeling. Just keep in mind, these shops make a living building Jeeps: buyer beware! Always do your homework, extensively, on any suspension lift and/or other shop work you have done. Cultivating some friendships with several certified mechanics is to your advantage if you decide to modify your Jeep.

Personally, if I lived in the Boston Area I wouldn't even bother modifying my Jeep. I suspect the Unlimited will handle just about all the trails available in Western Massachusetts. Bob's recommendation to install a winch and purchase recovery gear is sound advice. And, most likely all you'll need for your Unlimited for easy to moderate trails in NE. You need to understand, four wheeling is first about learning to drive offroad. Your Jeep is the most trail ready rig that Jeep has made over its long history, only the Rubicon has more capabilities. You need to go offroad (stay on designated Jeep trails) to acquire the driving skills and knowldege necessary. Your Jeep buddies will help you acquire this knowledge quickly.

Have fun with your new Jeep! <img src="/forums/images/graemlins/cheers.gif" alt="" />