Sounds like a great rig. Had the LMTV been an option for me in 2011 when I started my build at GXV, I likely would have chosen that over the U500(which I love), due to lack of places to work on them (not that I don't like visiting Rob in California). That said, all mine has needed is routine maintenance. After driving my GXV for 4 years now, the only thing I would have done differently on the cabin, is to not have the opening from cab to cabin. It has seldom been used, was just an added expense and something else that can break (and has). My pass through is likely not as easy to access as yours will be, since we left 3 seats in the cab, to take the grandchild with us occasionally. My wife, would likely not agree with me on not having the pass-thru, though, as she likes it.
While we don't live in ours, there is so much room, that even on a month long trip, we never use all the available space. I have seen some of the cool stuff Mike is doing to the inside of the cabs of those LMTV's, and they are really nice when he is done with them.