As much as you probably don't want to, I'd suggest you go in and talk to a dealer. Their ordering process is probably more flexible than what is available on line to you. Sometimes you need to know how to "get around things" in software programs - if there's a way to do it, the sales people will have figured it out. And as someone suggested, go see the commercial salesman at the dealership as they have to meet all sorts of different companies needs.
And yes, get the 4WD, I've never owned a truck without it. You'll probably get better resale value in the end.
Bill