Looked at the catalog, didn't see a thread about NH, so let's start one? Cause I need some help /out/

Where should my gf and I go camping in NH?
We're going tent/car camping for 4 days. I have no clue where to go.

Picking a campground is easy, but is there any non-site trails we can park, hike, find a spot and set up camp? Somewhere we don't have to pay for a spot, where it's legal to just go to and camp out. If that's actually possible in NH, I don't know. That's why I'm asking you guys

What area of NH do you like to be /out/ in?

Also, are there any specific things I should bring, or just the standard camping/hiking stuff?