Check out class 6 roads. NH has tons of them. They are unmaintained roads that make great wheeling for stock trucks.
Also look here for some info on clubs to join.
http://forum.neow.net/
BTW, some clubs are exclusive to jeeps, or yotas. I know of a few jeep only clubs and a few clubs that are open to everyone but they are a jeep club by name. North east toyota crawlers for example is a yota club but their president wheels a Samari.
The best way to go wheeling is to join a club. Clubs try to do it right. Legally, and cleanly. They also allow you to meet other people that are into the same thing.
The people that i know and myself included are typically cautious about just telling random people about places to wheel. It has happened many times where a great place that has been treated well by the people that were useing it was found out by the wrong people, those that just go and rip it up and make a mess, are loud and obnoxious. So now we need to get to know the people that we are taking to different trails and what not to try to weed out the bad seed so that we dont all loose out.