We have camped as a family - 3 generations- for a number of Thanksgivings. either in state park or on private land... tend towards state park as no water on private land. Not sure what we will do this year.
We have also camped a number of Easters. If missing church is a concern, for Easter, it is usually pretty easy to find somewhere nearby that is having Sunrise Service.. and when camping in a state park it is easy to find somewhere that you can have your own private time to reflect on the glories of our world.