Some states (including Virginia, by the way) have what they call a "Trip Permit" that you can buy, which solves all the problems. (Not to be confused with a wide-load type permit.)
With Virginia, this can be purchased online, for $5. You can use it to move an unregistered vehicle that you own, or to move a vehicle that you have just purchased (if you are going to look, and don't have all the info on the vehicle, that's okay too).
The permit is good for three days from when you want it to start (may be started after you buy it). You print it out, tape it in the window, and yer legal
I don't think all states have it, but it's worth checking into.
Raya