I bought four 12V 30W flood lights for exterior lighting. I started off by buying one of these lights, which can be seen on the back of the truck in one of the photos above, near the roof. I bought one to make sure they weren't a waste of money. A single light is probably enough light for my needs, so two should be substantially better.
The truck will get two lights facing the rear and two on the passenger side wall, facing outward.
The big key here is that they're DC lights. That way, I won't have to run the generator every time I want to turn the lights on outside.
12V 24V Truck Fish Boat 30W Cool White LED Wall Pack Wash Flood Garden Light | eBay