Mt Rushmore is the one place that we have been where they encourage dispersed camping. Some roads are not suitable for big rigs, but many are. Stop by the Park Office. They will give you road use maps. Enjoy!
No dispersed camping in Yellowstone. We stayed at a KOA outside the west gate of Yellowstone on Oct 10th. They were closing for the season that day.
We called Yellowstone today and they said there is a $500 fine for boondocking. There is only one campsite open. It's called Madison. They said there is another one that is first come first serve. We appreciate the info. Thanks