I have a 6 x 12 with a v nose posted in the conversion section. It measures 7' 6'' wide to the outside of the fenders, and the tires actually stick out about an inch on each side. It's just a bit wider than my full size truck, but driven carefully I have no problem taking it on any forest roads I'd want to take my second home. And that's probably rougher roads than most would take. With 1/4'' paneling on the inside, the clear side to side measurement is 69'' so at 6' tall the only option is to sleep length wise. with the layout I did it seems to work, and we actually stumble over each other less than in any previous rig we've had, including a travel trailer and a class c that were both larger.
I also have a 5 x 10 utility trailer for general hauling. It definitely tracks directly behind a full size truck, so it doesn't require as much attention as towing the cargo trailer. That said, it would be tough to envision a comfortable layout for more than one person.
As for axles, mine both have standard springs. Since the cargo trailer is loaded almost to capacity it rides and tracks just fine. I've towed torsion sprung trailers in the past, and empty the do seem smoother and to track better, but once loaded I didn't notice much difference. The place I buy trailer parts from does say that the conventional springs are tougher, and I've heard of the torsion rubber failing when running many miles down washboard roads due to heat build up, but I've never personally seen it.
I hope all this info helps with your decision. And most importantly, please share pictures when you do pull the trigger. ;-)
