#1 What size generator would be appropriate to run the AC?
This unit has an electrical rating of 115V / 60Hz, 12A* / 11.8A.
#2 How effective is this air conditioner in extreme heat?
This unit is effective in a heat environment, they're best suited for areas with moderate humidity levels. So they are most effective in arid climates.
#3 What is the diameter of the hose? Is a sliding door kit available?
The hose measurement is (1 - 5.1" Dia X 59"Length. A window kit is comes with this model.