I have much the same rig... Just older. I'm on the heavy side with a combined weight of 46K lbs and after 70K miles my MPG is 6.9 with a heavy right foot. Even at that weight I'm happy with the 400 HP 99% of the time. At 10,000'+ the turbo boost starts to drop off.
I still do back to back 12+ hour days as it handles that well... Do a search RR10S. Windy days or passing 18 wheelers is not a problem.
With the fuel tank not right behind the front axle you can use more of the 9000+ lbs of CCC. The barn doors make it easier to access things in the basement.
Monaco's good customer support is alive and well... If you need it. A lot of MH for $150K and 50K miles.
It makes a great boondocking machine as we usually do five week days in a USFS CG and then resupply and move on the weekends. We are half timers and love the room from the four slides... Especially the two in the LR.