Last time I "wilderness" camped (and I use the term "wilderness" loosely), was in Brown County. Nice camping area, but *nothing* to do. That's a tough sell when you're trying to entertain a kid for more than a day.
We camp almost every weekend in July and August with our 4-year old. What we do is make him part of the set up, maintenance and break down of the camp site. He feels like part of the experience.
We also try and take him fishing or do an activity each day.
My son also shares my love of campfires. I always tell people that "I camp to burn". It doesn't matter how hot it is, a bonfire is always on the itinerary.
Last summer and fall when campfire bans were prevalent, we chose campgrounds based on where I could have a fire.