Zion

Yeah, another vote for Watchman. Flush toilets as noted. But more importantly, the CG is right by the Virgin "River". But fall, it is a slow moving stream. Kids love to play in the water, build dams, etc. All the things kids love to do in a stream. There are huge Cottonwood trees all along the river, so on hot days (yes they heppen even in September) adults take their lawn chairs and put their feet in the river. As noted, you can walk to the visitors center and catch the bus up the canyon (the only way one can get up there) so you don't have to worry about finding a parking spot. There's also a shuttle into Springdale so unless you want to go farther afield, once you park your rig at thr CG, you don't have to move it.

There are electric hookups in a number of the campsites, but if you fill your tanks and have to empty them during the middle of your stay, it is still worth the bother because the CG is just that nice. (Make sure the kids know to only use the campground toilets to save water and tank space).