My bumper pull toy hauler was only 26' overall in length, but over 11K lbs. I always felt comfortable towing it with my 2005 F250 PSD. I really did not want something longer than 50' nose to tail because of the some of the campsites we visit and the ferries we use to cross waterways, but I would not hesitate to tow something longer if I planned to stay in open spaces.
Something others have not mentioned is how much overhang is on the rear and how low it sits. Obviously you will get tail swing when make corners, but you can also get tail drag on just about any driveway entry with the lower slung longer units.