I have a 6x12 enclosed but never used it for the bike. It has a ramp door and a side man door, very nice to have. I bought it new but on a used one look for rust, tire dry rot, make sure they spin free, get one with a drop ramp as they are much easier to deal with. Wood will be fine if it's treated but can get slick when wet. There's others who trailer bikes more than I do so they'll know better.