What? Oak not weather resistant? Better tell the Navy!
Heart of Oak Seriously:
I have a friend who is a keen woodworker. He thinks I should use teak or the more reasonably priced purple heart. These will weather well without a finish. Since the truck we are building will not be a work truck, I am thinking we will choose the wood based on color and grain and protect it with clear polyurethane.
I will probably go to these guys who are near me to make my final choice:
West Wind Hardwood Check their price list - there are descriptions and pictures of many types of hardwoods.