It is somewhat difficult to trailer a Ram dually. They are generally too wide and too heavy for anything less than a triple axle or tandem dual wheel gooseneck flatbed like hotshotters use. U-Haul and other rental companies don't have a trailer large or strong enough. I know because I once looked into haulling one in case I had a break down. No luck. Fortunately I never had the breakdown.
The only way you are likely to get it hauled is by an OTR flatbed tractor trailer wanting a backhaul. That would depend on luck and finding someone who was in VA and wanted to travel toward MT. I don't know if any regular freight routes run from VA to near Billings where you want it hauled.
In order to get someone to drive it for you the truck will have to be registered and insured by you. The seller is going to keep his license plates in most states, cancel the registration immediately, and cancel his insurance.
Unless someone in VA particularly wants a free trip from VA to MT it is not going to be easy to get someone to fly to VA, drive your truck to MT, and fly home again. You might find a sailor or marine in VA who lives in MT and wants a cheap way to get home if you advertise in local Craig's List in Richmond and Norfolk, Virginia Beach.
I suppose if the truck is registered and insured by you a driver with a small car with a towbar might be willing to hook his car on the back of your truck, drive it to MT, and drive his small car back home. Nobody is going to be willing to do that unless you are paying well.