Just a few thoughts from this old bus man. . .
~~ The MC-7 was the foundation that the MC-8 and MC-9 were based on. Ruggedly built, but with a few quirks, some of which have already been pointed out.
~~ They are prone to overheating if the cooling system is neglected, especially all the sealing around the radiators and various access doors. That and a driver that's not paying attention, especially pulling grades.
~~ Originally built with a drop-center aisle, unlike all subsequent MCIs. I noticed in one of the pics that CC leveled the floor, w/o a roof raise. If you're over 5'11", you may find yourself scrunching over as you walk thru the coach.
~~ Interior layout looks typical CC, seen lots over the years. As somebody else mentioned, when you combine the exterior paint livery with the interior colors, it looks a lot like one of the coaches used by McDonald's back in that time frame. IIRC, altho based out of Chicago, they were scattered around the country for use by various franchisees as promotional vehicles, as well as regional travel by corporate folk. I believe McD's had a contract w/ Greyhound to have them serviced by GLI's maintenance departments.
~~ As has already been requested, get the Serial Number and Unit Number off the coach. If CC removed the plaque from the ceiling over the driver, you may have to do some digging (but then again, it might still be there, just covered up by the overhead cabinet with all the system switches & gauges). The other location is on the blower box wall, above the sight glass in the cooling system recovery tank.
~~ Unless somebody's changed over the power-assisted steering to the Sheppard box, be prepared for a turning circle quite a bit larger than the 35' buses. Might be a factor wiggling into some campgrounds?
Lots to check out, keep us posted!
FWIW & HTH. . .
PS: There's a couple of 4106s for sale on Craigslist right now. . . as well as Macgyver's burned 4905.