I use synthetic and my vehicles go 5000 miles. My jeep just turned 106,000 and replaced the battery only. other trucks, K-5 Blazers both went over 225,000 with no motor
problems. The motorhome will be the same for me. Find a local shop and stop by. The local guy that's been there a while may just do it in the driveway to earn your business.
I absolutely positively stay away from the roadside quick lube jiffy lube whatever.
I did an oil analysis on my diesel pick up and they said 6500 miles. Keep it local if you can, support the guy thats been shlepping in your town for all these years.
Anyone ever have it done at the truck stops? Im sure the diesel pushers must have.