cooling the cab

Roof hatch like rally cars. Foot vent like early cruisers/f trucks.

OBT

Spray bottle of water... A squirt no and then evaporative cooling .... lovely.

Wet towel around you kneck too.

Take your shirt, shoes and socks off.

Now for the real answers LOL .
I have this paint on the troopy and it works . On a hot day i can get in and not be so hot that it takes your breath away . Paint it on the cab and the caravan as well .
Its so cool paint .
The only interior fan that really works is a yachties fan .
Yachties fan
An exterior metal sunvisor is a must for stopping heat getting into the cab .

Kevin,
Can you fit aftermarket A/con (they may still be available from the well known autoparts suppliers, Super-Cheap, Auto-Pro and similar.

Another tip that works well particularly with cab-over units is to put a layer of building insulation foil (looks like alfoil bubblewrap) under the floor matting and the engine cover. It helps with reducing engine noise too.

Another idea that may help if you can fit it on your vehicle is a tropical roof fitted about 30-40mm above the cab roof.

Legal Window tint on side windows will also reduce heat in the cab.

Hope this helps

Disco.

Kevin.
I don't use the aircon in my truck. The way I stay cool is to have bulk air through the cabin. The cheap and easy way to do this is to get a second hand sun roof out of a wreck and then install it in your roof but put it in backwards, that is with the opening at the front, there is a secondary benefit with this and that is you get a slight positive pressure in the cabin, it stops any dust from coming in. Eric.

What sort of vehicle is it Kevin?

seems to me i'll just have to start out early and stop when it gets hot at the closest c/p to use my aircon inside.
or make camp early and start the genny