I have a pole barn for my toys. You will need a 14' door.
My building is 24' wide x 52' long. I am just barely able to keep my truck hooked up to my 5er and close the door if I want to. If I had to do it again, I would do a little wider.
When I built mine 4 years ago it was less expensive to do wood than steel, and IMO it fits in better in my neighborhood.
Some advice. As others said, build as big as you can, bigger than you think you will need. You will never say you have too much space. Put more steel than you think you need into the concrete. You don't want it to crack. The more natural light you have the better. Skylights, big windows, and lots of them will make you happy. Electric outlets every 8'. Don't forget the outlets and lights on the outside of the building as well.
Here's mine. Again, there are some things I would change if I were to do it again, but overall I am very happy. You can PM me if you want to know costs.



