If you go the panel route. LMC Truck sells the replacement panels.

It seems all Rangers roust out on the passenger side front first. I had to do a patch job myself on my .98. I also did a beef up job on the driver's side. Cleaned, primed, and undercoated the crap out of it. Heculined the bed the seal the inside too. While you are at it, you might wanna look at your wheels wells. I had some water seepage at the weld points on the top. I cleaned the crap out for them and undercoated those too. They were only just starting to rust on the inside of the bed, so that should have been good enough to fix the problem.

__________________
Sgtsandman's Work in Progress
2011 Ranger XLT, 4X4, 4 door Super Cab. 4.0L, 5 Speed M50D-R1HD, 3.73:1, 8.8" open differential, Jason Pace cap
2019 Ford Ranger STX FX4, Super Crew, 2.3L Ecoboost, 10 speed automatic, 3.73:1 with rear locker, Leer 100XR cap