The facts as I know them. You are in this forum, so any truck with a idi is going to need work, unless you find the rare one that has been redone.
If it had the E4OD, it's going to need rebuilt, but so many of them fouled up you might get one that has been rebuilt already, cross your fingers that it was updated at the same time.
Most of these trucks have the ttb frontend. Most people do not like them because they buy it after it's already wore out. Frontend work on these trucks is expensive, and most will be worn out when you buy one.
If you are getting one with a zf, more than likely if the clutch hasn't been replaced and a conversion kit installed, you are looking at a expensive clutch job, since the DMF is certainly wore out by now.
These radiators are getting old, most of them are clogged or so thin they are ready to leak. There are a lot of threads on here about what radiator works best, and how to deal with the clutch on the fan. Because most are worn out by now.
Have the o-rings and lines been replaced on the fuel system? Another job that needs to be done.
You live in Florida, so you might be able to find a truck that is not rusted up too bad, I don't know. I do know if you get one, you might have a hard time finding used parts. When I was on vacation down there and had a injector line crack, finding a junkyard with a idi diesel was almost impossible. I went to every junkyard in Pensacola and after one yard would send me to another, and that yard would send me to another, I finally found 1 that had a 6.9 laying in the engine shed.
Yes these trucks are simple, they are pretty much the latest truck you can buy that have no emissions on them, but they are getting old and are going to require some work.