@mezger996 re: keep or replace.... it's up to you really, its the old devil you know vs devil you don't - you know your truck and maintenance history of it.
You state you don't want to spend more except for maintenance, but will it cost you less to maybe have someone cut and weld new patches into those areas vs. time spent looking at replacements, obtaining replacements, dealing with the surprises from said replacement?
If it really is a beater, then do whatever the minimum is necessary to keep it (somewhat) safely on the road.
Or, spend the $ on a replacement beater.
Or, keep it and buy another one, because 2 is 1 and 1 is none.
edit: found link I bookmarked where someone addresses this and the rear body rust:
I am the new guy that started that thread!
It's fitting to discuss here because I sold the car and bought one that is rust free. It was approximately 2 times the price, probably 3 once I factor in some other expenses related to the purchase.
I think there are merits to both approaches.
If I could have kept them both and designated one as a winter beater I probably would have done that. Especially if I was a high mileage driver with a daily commute.
Once you have reached a point that you have to address body damage rust, it's a whole different scenario. Unfortunately mine had reached that point. A quote to fix just that one spot, was between 1500 and 3000, not including rubberizing the wheel well and doing the paint. This was the one place in the state I trusted to do the work. I got a lower quote of 1100 from a guy who I think was just gonna patch it up.
Fluid film / wool wax can prevent if you are diligent about it's application. Like, you get into every single rocker panel etc, drilling if necessary. The rust repair place I went to, that applies wool wax, the guy that owns that company has a 90s pick up truck with 300k miles that looks like it spent its life in the pacific northwest. I looked all over / under it and was astounded at how good of shape it was in.
Having said that, I was prepared to bite the bullet and restore everything for the 99 I bought. I just had a last minute opportunity to bail and took it. If that one for sale hadn't come my way, I would have been (relatively) happy to repair the damage and move on and enjoy the vehicle. I wanted some features of a newer model to boot.
Honestly I think it's awesome to keep things running as long as possible, and welding together and repairing rust damage where necessary. That is what I will do with this car.
But it's so much nicer to start with a clean slate. I think it would come down to how much you want to take on another project, or your financial circumstances. These trucks have enough age that there's no avoiding looming maintenance. And trucks in the rust free areas sell for quite a bit more from what I've seen.
We live in a world where we can trade money for peace of mind. That's basically your option here! I think having pictures of the rest of the vehicle would help a lot.
Looking around at other examples, my car has so much maintenance done. Time for a beer 