I've driven through the reservation here in Wyoming and the Navajo reservation in Arizona. Firearms are locked in a case and out of sight. I've never been stopped. I've never been off the main roads either. Worst case scenario might be an auto accident where the cased firearms became visible.

We get tourists here who want to go the reservation expecting it be sort of like Disneyland. There's a casino near Riverton, but other than that there's nothing to do or see specific to the native American residents.