It does look pretty dry and solid underneath from what I can tell....it certainly doesn't look like your typical crusty northern rust belt special.
I would first concentrate on cleaning the car up, then assess what's needed to make it roadworthy.
Flush the tank, change all the fluids, possibly have the carb rebuilt...new plugs, cap, rotor, wires...new battery of course. If you can get it for a few hundred less, that's money to help make it road ready.
If not, the car still seems like a killer deal.