The most critical factors are #4 and #1 on your list. These far outweigh all others with respect to experiencing the lowest operating cost and highest reliability.
The chassis must be rust free and have full functioning running gear.
...and have full functioning running gear.
Move the '35 requirement down or less important. Many other factors take priority.
I also have an MCI MC-5C Saudi Bus. With a 6V-71 and the Allison MT644. Ya its slow up hills but will go 68 on the flats. We just got back from an 8,000 mile trip up the country with no problems. A few leaks but no big.
We'd love to know more about your experiences with it.
I wonder if anyone has heat rejection numbers for 8V-92 @ 350,380, or 400 hp
I posted it here a few months back 2250 to 2500 btu per min X each hp it gets up there