I have 308K on my 01, it weighs 10k all the time and often pulls 6K trailer.
Engine oil - Cenex TMS 10-30 winter, 15-40 spring, summer, fall. Change every 100-125hrs. Wix, Balwin or Fleetguard filters.
I have run synthetic Amsoil from time to time, 300hrs (10K) or so. After that many hours, it starts burning a lot of oil and it's cheaper to change it out.
On the Cenex oil, it will be near add after 100-150hrs. It will burn the Amsoil the same and after I start adding oil, it burns a quart to 1000 miles.
Fuel filter - change 10K or 200-250hrs
Auto Trans - Synthetic chrysler ATF every 25-30K
Differentials - Synthetic 85-140 Chrysler, change every 25-30K on rear, almost never on front. Rear differential is hottest running part of the ride especially if towing anything, often gets forgotten/overlooked.
I use the Cenex on the engine because I run it in all of my tractors on the farm, I have it readily available and don't have to buy special oil. I use the chrysler products on the trans on diffs because I usually have them serviced at my chysler dealer.
FWIW
Matt