if you are in NH, you need to join a club so you can wheel at Field and Forest. Probably the best trails in new england and definitely in NH. 3.5" lift and 35's will get you through the green trails (with some help probably) but anything more than that will require at least one locker or you will be beating the crap out of your rig. Although a guy in my club did run some blues in a 2 door on 35's and 3.21's. He just had to spin wheels like mad which leads to breakage when boucing on rocks. That will be your biggest issue on NH trails. Even though a lot of the class VI roads are dirt/mud with hill climbs, you will most likely run into rock areas that require momentum to get over unless you are geared properly or locked. Bouncing equals breaking and that dana 30 can only be beefed up so much.
With that said, I am one of those that would rather go with what I have and replace it when it breaks. Some gussets and sleeves or truss will help for a while. If you have alternative means of transportation if you break, it is your better and cheaper option. Start saving and hopefully if it breaks, you are sitiing on enough cash to get the d60 up front!
Good luck with your build! You should take a look at the NEA 4x4 web page for clubs to join. I am not kidding when I say Field and Forest is AWESOME!!