My landscape architecture courses (4 years, night school) were at a good university but weren't part of a degree program; they were a function of a very good university extension program. After that and two years of internship, I took a national licensing test and passed the damned thing (3 days, yikes).
My point though is that the beginning classes were not about landscape as such, but about the elements of designing, and those elements set me up for later more particular learning.
Does a university you like have an extension program? with any kind of non IT design classes? You can usually pick one class at a time, one amount of money at a time. Nothing like tens of thousands.
So - that's one thing, maybe just hop into some basic design classes. You might want to go in different directions after that - to mechanical/industrial/automotive engineering, whatever.
Sounds like you are in the eastern US. Check out Pratt Institute for certificate programs (sounds mildly similar to classes I took)
I think what you are looking for is more knowledge and not necessarily a piece of paper, but you might get to liking all you're learning and go for the paper too.
I also like the kickstarter idea, and I know there are other sites somewhat similar to kickstarter. Can't remember the name of one right now.
On business school, lot of people do that and while some courses would sure be useful, a whole degree? Maybe more extension programs. UCLA's extension system is fabulous for a whole lot of subjects, same with other UC schools. I don't know how these things work in the eastern US.
I don't know, re business school for the degree. You still wouldn't be in the throes of how to design things.
So, it's up to you, what you think you will enjoy.
You can tell I'm in favor of one's work life being of continuing interest.