Welcome yzeevy,
Glad to see your thread. Your new truck ambulance really looks good.
Had to laugh at your questions about the electrical spaghetti and unique wiring solutions that ambos have.
Think you are right about the separate AC and generator that are needed in hot areas.
I have a 96 Ford E350 with an Osage ambulance package on the rear that served as an oilfield service truck/mobile office for 1.5 years all over Texas.
One of your pictures looks like you opened up your outside vertical compartment on the far back, driver's side. Looks like the generator could sit low, have a middle sealed compartment (with access inside or outside as you want,) and use the upper compartment for the 115 v AC unit. Both the lower and upper compartments could vent in two (or three) directions with easy mods. With additional openings/vents on the driver's side and the rear, hot air and gas fumes would dissipate rapidly. Additional openings in the top and bottom are easy also if further ventilation is needed.
On my ambulance, my preferred outside sitting and BS area is on the driver's side or to the rear, out both doors. The generator and AC on the rear corner might be noisy from the outside and perhaps the other side rear corner might be best. (On my ambulance, the oxygen bottle storage compartment is behind the driver and this would be my preferred generator and AC location. Would get additional ventilation from both sides at the body corners, be out of the way, and lower generator access from both sides.)
Took the light bar off, but still have the protruding aluminum mounting arms. Thinking about running two 6.5' long sections of 6” black plastic pipe up there to make a solar shower out of. Want to relocate my single spare to cab roof-top carry to free up storage compartments.
Took the red lenses off the ambulance body and painted them inside and outside white. Doesn't really take away from the ambulance look. On the driver's side, then removed the red flashing Whelen lights and riveted a white rectangular piece of aluminum with caulking. Those look good.
Some people of this forum have replaces their red flashing lights with pieces of the shiny aluminum tread plate, which looks ok. The white aluminum pieces look the best.
Keep us posted and remember to take some time off just to enjoy the good life.