If it is original paint and the interior looks as good, $5000 and a good detailing would have you guys gushing over the survivor HP2 car. Not every car deserves or needs a nut and bolt restoration.
Trying to help the new member, I asked if the paint was original. If so, it might be polished and good to go. They needed to be asked more about the rust. if the only rust was the flaking paint on the rockers, it is still an easy fix down low and not expensive if you do your own work. Reading between the lines, the car loosened bearings years ago, the broken motor torn down and forgotten and along with the parts, parked inside. The motor is in parts, so the cost to assemble depends on mileage and how many of the original parts remain. If low mileage and everything was in the garage, a ra-ring kit and hone could have it running. I would ask the machine shop to take it easy on the paint if they could.
I didn't think it was allowed to comment on For Sale ads or I would have offered help to improve the listing. Instead, the newbie was attacked. Now it's selling on flakebook when we might have convinced him or her that they could, with the help of friendly members, fix and drive this gem in the rough they probably inherited.