NC, your wife must not like pretty rocks like mine does! I am at 27K with my RV empty! With our 36SB3 we were 28-29K.
Vett Racer I would take truck in to dealer and have it flashed if you think it is dropping a gear before it should. I hold 6th on hills towing 33-35K combined but it does down shifts as needed. I will drop a gear before it needs if I see I am coming to a grade that will require the gear drop it just makes it seamless as the computer can't know what's coming.
You guys would have both been just as happy with 3.42's with your loads towing in 5th.