That covers you legally, but I’m talking about the expense. If it’s something you can grow into, you’ll probably make fewer missteps.
I’d start with a really thorough assessment of the outbuilding, and come up with a priorities list of improvements. If you have access to a thermal camera, they’re really useful. If you can add even more insulation, all the better. If there are opportunities for pests to get in, they’re probably going to.
The lighting isn’t that hard to solve for, and it’s pretty much about throwing money at the problem. I’ve found that it’s the other stuff that has me chasing my tail.