Welcome to the addiction!
Here's something to consider, based on my own experience with buying a trailer frame and not having a place to work on it...if you go with a small cargo trailer, you will have a "workshop" of sorts in the trailer itself. Battery operated tools are awesome when you don't have an electric outlet at your building site. Storage facilities will often have spaces for trailers, and cargo trailers do fine outside. Some storage areas won't let you work on your vehicle onsite, though. You can generally find someone who will pull a trailer for you to a location of your choice, so you don't absolutely need a tow vehicle right away. Cargo trailers lend themselves to many design options, but they definitely lack the "cute" factor that teardrops and small canned hams have.
Good luck with whatever route you choose. You sound very determined. And with your design background, you might stumble onto a second career you weren't expecting!