It's a real tough market to sell a project, especially a "major tear down" such as yours.
First off, you have an idea of the money involved in finishing it and the amount of work still ahead of you. An educated buyer should also realize the cost involved in buying a project of this magnatude and quickly realize he can buy a "done car" for less.
Although your car has a nice desirable colour combo, it's still just a 383 Auto, pretty low on the food chain as far as 70 Road Runners are concerned. You would have to find a buyer that just needs to have it...
I'm sure you have $10K+ invested, but I can't really see anyone paying anywhere close to that...
Some reassembly would help the sale, but not by much in my opinion.
If you truely want to move it.....EBay with no reserve will be a quick indicator of what someone will pay.