Thanks to all the folks who made recs for Jackson Hole, and Casper. We just got back and here are the best of what we had:
Jackson: Had a great meal at The Blue Lion...a couple of blocks from the square, outdoor patio, or indoor seating, and great food too. But an even better place was in:
Casper: The 303 Grill was outstanding. It was beautiful and delicious. They had no kid's menu, but happily made my son the best fettucini alfredo any of us had ever tasted, and for a very reasonable $5.00
Sundance: ARO was a great little cafe for lunch, just as we'd heard. Good food, low prices, friendly staff.
Riverton: There is hardly anything in this town...but we saw a holistic, gluten free store, and walked in to find a lovely buffet with organic foods, great salads and hot dishes too, yummy desserts, and more. This was a great find for lunch and the staff there too,was friendly, and knowledgable. It's called Graham's, for anyone who finds themselves in that area.
Yellowstone was beautful, and while I expected very rustic fare there, we were surprised to find wonderful food at the Mammoth Hot Springs dining room, the Old Faithful Inn, and at the Grant Village restaurant. The more casual places weren't anything to write home about though....cafeteria food.
Thanks again to those who recommended places.