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

I don't think climbing through the window is practical for anyone but the smallest person. I'd probably do a Class B. It doesn't look as much like an RV.

If you are dead set on a TC, I'd look for a used Northern Lite in the Northwest and use whatever you have left on the truck. If you are buying used, resale value isn't your friend. I think you'd be better off with the simplest cheapest model which is why I was suggesting Northern Lite. A 90s vintage would help you save a lot of money for the truck.