I have a 23' Dolphin with a manual 22R 4cyl engine. I have logged 30,000 miles on mostly mountainous terrain in the southwest and Colorado. Yes, on super steep grades it is very slow, but so are alot of other RV's out there. Have never had any engine troubles associated with this.
I do alot of backwoods adventures on graded gravel forest roads and have driven very slowly and carefully on some worse dirt roads. Keep in mind that slow and gentle beats replacing broken parts that an older unit might get from undue stress and vibration.
