Hi - I've got a 2016 Canyon Star 3712, stock suspension. It has an option on the front suspension, I don't know what it is offhand. I added the Five Star Tune to the engine/transmission for towing.
It handles just fine with or without the toad. The length does nothing to the driving characteristics. Maneuvering around the gas station, however, it does become a factor. I don't get gas at many places simply because I know I can't turn that 38 foot rig around safely in that tiny lot. Fortunately, it has a big gas tank, so I can pick and choose (Flying J), so its really not a problem.
The Five Star tune is a good deal. Some say you don't need it, and maybe you don't, I'm just very pleased that I got it. I don't have any problems driving, passing, and whatever. I'm not in a hurry. I encourage people to get around me and get away from me. I haven't climbed the Sisters on I80 or climbed I70 on the other side of Denver. I did in my 1994 Kountry Aire at 3MPH with the big boys. I bet my Canyon Star would do better.
If I had any negative, I'd say this rig tends to rock back and forth a bit much in high winds. Maybe that is a built in indicator to tell me to get off the road in high winds
Keep the questions coming!