'04 coach w/ an Onan QD10KW here w/ 3400+ hours - lots of dry camping - track side, college tailgating and LONG LONG road trips (back and forth to virginia, florida) in the summer sleeping in rest areas.
we have an old english sheep dog (120 lbs)...and if she's in the coach we're running the air conditioners.
engine doesnt burn a DROP one of oil, I had one (freak) problem with it where the stator shorted (bolt came outta the motor electric motor mount & i think it vibrated and wore the winding) we replaced it the stator (ouch) and we've put at least another 500 hours on it since then.