Thoughts on a Chevy 8.1L Gas Engine vintage 2003

I have a 2003 Itasca Sunova with the 8.1 and pull a 4000 lb GMC Canyon pickup. We've had it out west in the Rockies several times and this year out east over the Appalachian Mtns to the Outer Banks with no problems with the power train. The hardest climbs were last year when the unit was 12 years old on I70 west of Denver at the Loveland Pass and the Vail Pass. Seemed like they took forever but we made it.