We are new to this, but came up with some things we heard might be cool. One is my DW bought a pack of small canvases from the art supply store they are 8x10 I think, and some brushes and paints. On our first RV trip, one activity was to paint a masterpiece of our campsite. After they dried we hung them in the RV with some of those 3M velcro things. We will continue this project as they really enjoyed it.
We do all the standards, smores, hot dogs etc. over the fire. We are going to get a popcorn basket thing, as popcorn is a family staple. The kids are good about making up activities.
I do surprise them with things I pack in the RV before we leave without them knowing. Scooters, etc. so they are surprised I brought them.
The most important thing is being with your kids. Even emptying the pooper tank can be a good memory if you have the right attitude!
Enjoy your kids, they grow way to fast.