Just made that trip last August. Came into Grand Teton from Jackson Hole. Stayed at Colter Bay RV Park in the park. The only campsite with full hook ups. If you paln to stay at Colter Bay you better make reservations NOW!!! You can easily get into Yellowstone from Grand Teton. We did that with our toad. Just make sure that you get the senior card which will save you lots of money going into National Parks. The campgrounds in Yellowstone are not good, very old not made for larger RVs. Stay in Grand Teton and drive into Yellowstone.