I use Dodge recommendation of 7500/15000 miles on my '03 HO and use nothing but Rotella dino. The Cummins has just over 325k miles now.
This truck pulls a 11200 lb 5th wheel trailer some times ....a 16k GN tri axle stock trailer and various other non rv trailers plus it was a daily driver for a while at 660 miles a week.
I use a mixture of the 7500/15000 miles schedule depending on percentage working or running around empty.