Depends, how long you planning to keep the truck.The reasonable quick fix is use a Dremel machine with a pointy grinder bit ,take off the rust not keeping the tool long on the metal, so you will not heat it up and damage a larger area.
Use a drop or two" rust converter "if cant get that, any good primer will do.When dry,work the paint on, drop by drop with the end of a bamboo skewer stick.
Leave it alone 10-12 days,then a little polishing cmpnd.and colored wax at the end.
It may sound crazy,but the bubbles trap water and soon you ending up with holes.
Or, of course you wait a year or two and part it out or have a body job done.
I have a 2001 with 135k,body is perfect but my frame is a write off.
Happy Days!:nopity: