Since I have a transit bus (AMGeneral)my generator set up is a little different. I made a generator compartment next to the driver's seat like a front engine (the generator engine faces back so the generator head fits under the dash floor.) I'm using an open Powertech 10kw of which they still make with the 4 cylinder Kubota and brushless alternator. I built a 1/4" thick steel floor with 1.5" angle iron around the perimeter to anchor the 3/4 plywood enclosure. Since the generator had to be installed through the front door, all servicing is done from inside, but from above the generator. With the 3/4" plywood enclosure, and 1" lead/foam sound insulation, you can't hear it running inside except for the vibration. When in the bedroom with the A/C on, you don't even notice the generator running.
I have a remote radiator with a single inlet squirrel cage blower belt driven off a 1/2hp 2spd fan cooled totally enclosed motor mounted under the driver's seat exhausting out the left side. High speed during the day, low speed for quiet night time. Also an 8" inline bathroom ventilator to push air through the enclosure.
I highly recommend using an open generator and also a remote radiator. On my truck I'm using a Wrico 12kw with 3 cylinder Kubota that Dick Wright custom made for me that's only 36" long. Dick sold me a fan that uses only 5amps that blows really hard, but with a speed controller for the radiator. Good Luck, TomC