My tailgate has the same cancer that just about all 01's have - bottom right corner.
Questions:
Do all Gen 1 tailgates fit?
Did they change anything throughout the run to eliminate whatever the problem was? Meaning - is there a better year to look for at the bone yard for a replacement?

 

the tailgate rust was common on 98-00, 01-03 tend to be good (maybe it is all in how they were kept up) my 2002 has 0 rust on the body and very minimal rust underneath.

i believe that all liftgates will fit, but i would stick with 01-03 and make sure to bring a couple of friends with you to pull it off the junker.

 

Sharp - I am a wax fanatic. Not sure what more I could have doen to protect it other than taking care of the rust when it first popped.
I didn't - and it spread fast.

 

the big thing is catching it early, and whenever you see bare metal you need to touch it up immediately or sooner, i go over the truck every time i wax it (3 times a year usually) and sand down and touch up any spots that are through to the metal, also make sure that any drain holes are cleaned out so that water cannot puddle, idk how often you wax, but with modern waxes its not necessary to wax as often and you still maintain the same protective qualities.

Also i will add that leaving road salt and dirt on the paint will also cause rust so if you dont wash it frequently enough that will accelerate the process.(will rust from any tiny exposed spot and then work under the paint, not through the paint of course)

 

The only rust on my D is the d** front bumper going to have to replace it soon.
I have seen this on many Durango's tho.