The generator is in the rear on the passenger side. The window on the entry door can be cracked open a bit, similar to the ones on the sides in the rear. The back windows also open, but come with no screens.
The A/C works pretty well. Just the dash A/C is fine when driving, and the house A/C has kept us cool under most camping conditions. The exception was a no shade, 98 degree day, when it was still around 80 degrees in the Roadtrek. Not sure any A/C does better under those conditions.
I have the RT 190 Popular, based on the Chevy 3500 Express Van - might be a bit different for other models, especially the Sprinter models.
2013 RT 190-Popular