I found & bought a 99% perfect 2005 Yukon XL SLT 4 years ago. ( It has been 'perfect' since then)...... It was very difficult, but I put my '88 GMC C2500 ' Camper Package' , for sale.
I bought it with 8,000 miles on it in 1990 as I lived in Southern California.
I kept it running good.... engine area very clean.... underneath very clean..... at 220,000 miles I replaced the engine with a 4-bolt main 350...... I had 392,000 miles on it when it went to sale.
I had just replaced steering / suspension with Moog. The interior was pretty good, ( perfect dashboard, due to a dash cover from 1990)... but redid the bench seat like factory. ... I had & kept all paperwork, including the 'real' 3- set repair manuals.
I got contacted by an exporter in Florida looking for trucks as yours ( I live in Fl) and he bought the truck for $4,000. ( 4 years ago) To a collector in Germany.
DO NOT REPAINT IT !!!!! Unless it is done like factory........ The 'patina' kept the value!!
if you wish, the exporter pays top dollar for a truck like yours...( They LOVE them in Germany)
I can give you his #..... If you wish.....
.......What was cool, is the new German owner sent me a video driving the truck from the import shop in Germany. ( It was very cold outside ...exhaust steam )