Does anyone know if and where there is camping on the Virginia Creeper Trail?

You could contact these people.
https://www.vacreepertrail.org/

However I do know that it is allowed off the trail but I would advise gaining permission before trespassing on private property to do so.

This is a good site:
https://www.cccyclery.com/vacrep.htm

this has been a big help when looking for camping in va. www.dcr.state.va.us/ hope it helps.

For several miles north of Damascus, VA -- the Creeper shares the same path with the Appalachian Trail. I saw several flat places to camp along the Creeper (that runs parallel to a stream). They looked like campsites to me, but I'm not positive it is legal to camp there. If you camp along the AT section, it should be OK...
PS: There is also a free hostel in Damascus called "The Place"

Virgina Creeper isn't long enough to bother with camping along the trail.