Car hauler trailers

i have a 18 ft steel deck 3500lb axles that my dad bought new in the 1990s bought in mo. been a great trailer i would recommend at least a 20ft trailer, because when you get your car on the back bumper is only a few feet from back of trailer... if you ever get hit from behind the car gets hits before the trailer plus gives you more room to tie down depending on where the d rings are mounted
pulled this trailer with a2004 ram hemi 1500 all over and it pulled it fine, also pulled with a 4.7 engine which are junk engines and dont pull like the hemi or a diesel will.
also i have a 31ft stealth enclosed 10k trailer the 1500 will pull it power wise but dont have the braking or handling of a 3/4ton or 1ton truck, so anything over a 20 or 24ft enclosed i would get a 3/4 or 1 ton truck, and for gas mpg hemi well get like 11 to 13 mpg with open trailer and 8-10 with enclosed. diesel will get better mpg. hope this helps.