I think you just described my 240z purchase to a T. From the paying too much, to once being a CA car, down to all the rust problems that come with being in the NE for 25 years (in my case), as well as buying it anyway because of the excitement of being a 240z owner, and even the bad repairs, although mine had different repairs.
Be thankful that your car is actually salvageable. Mine is in MUCH worse condition, and I (stupidly) paid $300 more. Granted, I didn't know what I was going to find, even with what I could see in the guy's garage, which wasn't doing the car any favors.
Anyway, good luck with your project! The car actually doesn't look too bad.
Edit: Actually, now that I look at it, it's really not in bad