My boyfriend and I personally like finding our own secluded campsites that are not in state parks so our dogs can aimlessly run around and thoroughly enjoy the outdoors. We all actually went camping the other weekend and had an absolute blast. We found a beautiful campsite on the Georgia/South Carolina border near the Chattooga River.
My pug Jack and I got a little cold at night because the temperature dropped down to the low 30's, but I was able to cuddle up to him near the campfire to keep us both warm. Lilly on the other hand was not phased by the cold temperature due to her extremely thick and heavy fur. One of the smartest things we did this past camping trip was buying glow sticks and tying them to Jack and Lilly's collars so we could see where they were at all times after night fall. I would highly recommend this to anyone who goes camping with their dogs. Although I would not recommend to keep your dog unleashed if they have a tendency to wander away, especially at night.
Check out this awesome website that contains information on dog friendly campgrounds in the entire U.S. and even Canada!