If, perchance, you're going into or out of Yellowstone thru Cody, WY, plan to spend a day at the Buffalo Bill Historical Center. It'll take a day to see it all. It's really a collection of several museums in one place, including Buffalo Willy stuff, the Plains Indian Museum, the collections of various gun manufacturers and one of the finest collections of original western art you'll see anywhere, including Frederick Remington's studio and a ton of Charles Russell. Worth a detour or re-route and you'd enter (or exit) Yellowstone at the east entrance within spitting distance of Pahaska Teepee, Buffalo Willy's old hunting lodge. Nice campground near Wapiti, about halfway between the east entrance and Cody.