I'm starting to like those clean foh-doh familymobiles more and more. You could probably almost restore it with just a big soapy brush.
FYI: You describe the car as both "all original" and "mostly original". Which one it actually is might make a difference to someone.
I've got 3K. What I don't have is room for another car. fudge! I've never been a big fan of the later model "square" cars, but I'd take a 67-69 in a heartbeat.
I think value depends alot on where your prospective buyers live.
If its a Cali car, Cali guys won't pay as much as the east coast guys who would kill to get a clean rust-free body.