From what I understand, the guts of car would likely still outlast the body of the car, even with the repairs to the body.

Thoughts?
True that. The trick when buying a used vehicle is to check the underside of the floor pan. You're looking for a city car. Both of my '02's are city cars and even being driven is salt the fuel and brake lines look new. The 1998 on the other hand was driven on gravel roads frequently and as a result the stones thrown up by the front tires blasted the underside. In addition around here the gravel roads have chloride put on them during the summer to keep the dust down. So not only is the underside being blasted with stones it's being coated with chloride in the summer (corrosive) and salt in the winter (corrosive).

In your case, as long as the sub frame is solid and savable I would fix the car. If the sub frame is rotted then I would band aid it and keep an eye open for a sharp "city" car to be your next car.