You need to shop more for a TH...our CY has 17.6" advertised, 16' 8" actual length....full width (no slide in the garage) and have plenty of room for our 72" wide X3 Rock Crawler, both width and length with lounge rockers and more misc "stuff" in front and rear of the machine..
A note on our above specs...if the garage is advertised as XX' long and has the 3 season doors option, you may loose 10" like ours did. If you think 12' advertised length may be long enough, you'll be in for a rude awakening after purchase unless you measure that particular model. Good luck with your search..