I pulled an enclosed 20 foot trailer for many years behind my former 40 foot Monaco diesel pusher, mostly with race cars to race track, but often with a motorcycle and car on vacation. Very handy, vehicles are kept clean and protected, and you can throw other stuff into the trailer. Also has the advantage of being able to back up, which you can't do with 4wheel down or tow dolly. Main disadvantage is WEIGHT - an enclosed trailer alone is over 3500 pounds, and when you add a car you are probably approaching 7000 pounds.
I now flat tow a Mini Cooper with my Vegas....