We had a son that was in his 20's (we started early) and then had two daughters who are now 9 and 6. Both the daughters started camping when they were 4 months old.
We bathed them in our large crab pot and they slept in the pack n play. We would take the pack n play outside during the day and we used a mosquito net over it.
We, too, had a baby backpack that we utilized when we went hiking. We used it when we biked within the campground. (We would not have gotten on the highway with it, but inside the park was great.)
Once it warmed up, we had a small pool that we would put a few gallons of water in and placed under our canopy let them play in all day. We used plenty of sunscreen and never left them alone.
A large flannel-backed tablecloth is a great play yard for paints, playdough or many other play toys.
Good luck and just go with the flow. Let the fun happen.
We used many, many DVDs and a small DVD player. VeggieTales and Barbie movies were favorites.
2017 Ford F350 Crew Cab 6.7L 4x4 DRW