Can tickets still bought on site? Trying to get them online but says my email address is not valid

Check w/ the information centers around Medora, am sure they can accommodate two more.

Yeah we purchase stars at The Visitor Center when we went

You generally always buy on-site tickets. Check in at the Medora City Center, a block down from the Rough Rider Hotel. Have an awesome time.

Pretty sure you can

Yes you can