Check the jack points for rust although it's kinda strange having that out in desert J-Tree land.

Does the dash look like a dry riverbed? Do all of the vaccum locks work? Check for the typical leaks, oil pan, valve cover, PS pump. Lift up the floormats for rust. Are all the suspension pieces in decent shape? Tires/shocks in good condition. Does the AC work? Any idea if it is a York or an R4? The York is easy to identify by seing a massive chunk of metal on the left side of the motor (looking front to back) with two big hoses coming out of the top. 1979 is a split year for that AC unit.
If you get the car I might be interested in some of the parts. How is the driver seat? My 79 is in nice shape but the springs are a little low so perhaps it might be a good replacment?
If you get it and you're in the LA area shoot me a PM. I am looking for other 240D's to drag race! J/K