I love towing with a car instead of a truck. I don't have the cargo room, but I did average 22-23 at over 70mph.
My wife's little shopping cart (station wagon) had all the cargo room I could ever need and towed the ski like a charm. 85+ MPH all the way and mileage worked out just dandy.
No tickets for me though I did get extremely lucky just before Orlando.
A Cop pulled onto I4 as me and a nice blue 911 were cruising at about 90 MPH. I noticed the cop first and backed off but the cop totally ignored the wagon pulling a trailer and went straight for the Porsche, Can't blame him there.