I have two old tobacco barns. I turned one into a work shop, one side with ac/heat, the other side with two large doors for ventilation. I run large fans as well.
I concreted the floors and insulated/covered the a/c side and added tons of lights, improved the electric panel, etc.
I went with metal sheeting that I applied directly over the old barn wood. I re-roofed both as well.
The large barn is for equipment storage only.
I waited about 12 years before I did all of the above and can't believe how stupid I was for waiting so long.
During:
After (backside)
Frankly, I'd get the shop sorted first since stagging our of there will be a big deal as you move forward.
Great place!