Dinghy,
My Rv is a 35ft class A with the 8.1L V8. I have driven it from the east coast to west coast twice and all over the Rocky mountains towing a Jeep Liberty. My gross weight with both vehicles is 26,000 lb and we have not had any problems pulling the mountains but don't expect to go up real fast. I'm not familiar with the 6.0L but with your lower weight I think you will be ok
Tom
