[spacemanspif]

For the front wheels and the front of the rear wheels just make gap fillers out of coroplast to to encourage the air to pass over the wheel/tire and leave the rear open. This way there isn't interference with the turning wheels and your rear skirts don't have to look weird. For the front close up any gaps that exist that are not in front of the radiator like around the headlights and bumper. Belly pan would be nice but a huge ass air dam is easier. I can't see if the truck already has a dam, but it should have had one from the factory, I think. If you don't have one, get one, and then make it longer appoximately as low as your lowest piece (rear axle?) or a little lower.

Electric cooling fan of belt driven? Thought about a chip for the engine for eco and towing modes??