I'm thinking of planning to drive my camper into one of the Valley car camps next Summer. And then while my wife and son mind the camp I thought I'd try to get a permit and take a shuttle up to say Glaceir Point and go out overnight. Then hike back to my camper in the Valley. Anyone here ever done that?
No, but I can tell you what people have done. Get a permit and ride the tour bus (there is no shuttle) up to Glacier Point, hike the required four miles from the trailhead up Illouette Creek to camp, then hike back down to the Panorama Trail (there is no camping along this trail) and go over to Nevada Falls to rejoin the JMT or Mist Trail back to the valley via Happy Isles.
The camping restrictions around the valley are really specific because so many people do just an overnight that the area would be destroyed without careful management. The only places to camp in that region are very well defined by the rangers. They'll show you on the map. If you do decide to do this, you will need to reserve that permit as soon as you can. The other option is navigating the first come/first serve process (get the permit the day before you want to go) and that's pretty well delineated as well.