is a DVD of TR park available?

Most parks do offer brochures and dvds of the park. I would advise going to the site itself and contacting the Rangers office via email or phone call. Possibly check FAQs

Possibly at the visitor center.

There is an Rv park in Medora which is below the park. We have stayed there several times. It's a nice place

I was there subordinate your question?

I believe there is