We went through Grand Tetons and Yellowstone in mid June (about a month ago). If you are willing the go without hookups things are somewhat better. We stayed at Coulter Bay in Tetons and at Lewis Lake in Yellowstone, both without reservations.
Some thoughts -
- Checkout at both NPs, as I remember, is at 11am. Getting to the campground around that time increases the probability of finding a site someone has just vacated.
- Often a "occupied" slip is left on a campsite that has been vacated. I check the dates on the slips of interesting sites.
- "Campground Full" signs are not always updated quickly. Often worth checking, especially on a Monday morning.
- My wife is disabled and we carry her placard/documentation. Parks often have a few disabled sites, which may be available when the CG is otherwise full.
- The size of the Solera (24 ft) allows access to some CGs not available to longer rigs. As I remember, Lewis Lake is one such CG.
- We ask at the entrance gate about campsite availability. Response is often "I don't get official updates, but I heard there are sites available at...". These inputs have proven mostly correct for us.
Has worked for us - your experience might vary!
2012 Solera "S"
Calif SF Bay Area