I have $20,000 cash right now.. Can I afford this??

$20k should be no problem.
$10k camper will get you a nice one. Got my 03 AF for $9k. Wouldn't say it's like new but it's in very good shape, not a lot of use.
$10k will get you a pretty nice 2wd gasser truck too. If you're budget limited, don't bother with a diesel. youll either spend most of your $ to get a nice one or have a bomber for a truck. Unless you stumble on the right deal, but deals on any trucks are few and far between recently.