Is there a place to rent a dirt bike nearby and can you ride that in the sand dunes ?

I don't think dirt bikes are allowed, however there's a 4wheeled drive road https://www.nps.gov/grsa/planyourvisit/medano-pass-road.htm

At the vegan market maybe what kind of person wont eat a donut cuase of grease your a savage sir

They may have dirt bikes for rent in Alamosa. Part of the dunes are outside of the National Park out towards Crestone. Do a bit of research and I'm sure you can figure it out.

No dirt bikes on the dunes I think.

There isn't anywhere "nearby" the dunes, it's pretty secluded. I would be very surprised if they allowed dirt bikes on the dunes in a national park.