You're not a young man Steve. You can't take it with you. I don't want to see you working on the ground anymore either.I have used two cargo container on the farm for years. They are good storage ,but I am tired of working on the ground repairing equipment. If for a work area build a shop.
...and make it tall enough for a lift!^^^In that case, build the shop. You only live once.^^^
Beautiful garage doors!
I would build a shop, but knowing you, whatever size it is, you will fill it up. Now if you can fix that issue, you'll be styling