I have been hiking with a pit, and camping with a bull terrier. Off leash is NOT a good idea. Most campsites have a firm on leash policy. They can and will kick you out for disobeying it.
You will not be watching your dog every second. You may think you will, but you may need to tend the fire, or turn to talk to someone (all normal things) and that is when he will sneak off. And they WILL sneak off.
Also kids at campgrounds often run loose, and people's dogs are often totally unsocialized and leash barkers. They come out of nowhere, they come through your site sometimes. The kids can start screaming in the middle of the night because they are playing, or they are teens flirting. It is NOT the place for an off leash pit, or any other reactive dog, ie anything other than a newfoundland or a really fat old lab.
Do take him camping. I would bring a crate for in the tent-they can rip the side of a tent open in 5 second flat! Do proof him before hand on sounds in the night. Dogs used to quite houses often wake up barking at all the campground noises. I have even put the bull terrier in the car over night because it muffles sound better-both inside and outside the car.
Enjoy camping with the dogs, a dog lying by a campfire is a great thing. Take him on a few good hikes to tire him out too;-)