The oldest cars in daily use over here are about 30-35 years old. We put salt on our roads during the winter so the corrosion is really bad at times, cars without sufficient protection from rust from factory usually "melts away". The older part of the active vehicle fleet over here is mostly Volvos since they have the needed protection, they rust as well but at a slower rate so that you can keep up with the need for repairs.
It would be fun documenting the makeshift fixes and adaptations you mention. Might not be all that interesting for a culture where it's common, but here it's inspiring and impressive! We could need some of that "make it work" mentality!
The doctors gave me thumbs up for driving again this week, had my first drive yesterday and I felt really free! Drove to the gas station and filled up what fuel my mother had used up while borrowing the car. She drove about 240km and landed on 25.12MPG. She mostly drove to her work a 7km highway stretch away. I figure that the high consumption stems from the short trips, oils never reaching operating temperatures and such, and to some degree her pedal work. She complained that my car is slow, says a little about how she drives. ^^