I know that as parents of "busy" kids - you'd like to just sit and relax for a few moments :-) But your time to be invited to play, is very short. Pretty soon, the oldest would rather be with other kids her age - and God Forbid her parents would be hanging around....LOL! Once they get Driver's Licenses - their at-home social lives become critical and camping will be a dread subject. Actually - once they start driving, they tend to get summer jobs and all of a sudden they CAN'T go camping. Now you have a choice: leave them behind, or don't go camping?
So what I'm gently suggesting is to get up and go do what they want. The fact that they want you along is testimony to your being a fun parent :-) You're making great memories - stuff they will cherish. There will be a gap in their attendance, as they get into high school and maybe on to college.... but once they are hooked on camping, the bug will bite them again. And again, they will want to camp with you - and bring along their own families!
Trust me, when your grandchild wants to go find lightning bugs - you will HAPPILY take him/her by the hand and chase bugs!
It's the Camping Circle of Life. Of course, now, when I go to make reservations at a State Park, I have to reserve 4 or 5 sites at a time....LOL!