Weight limitations is a very popular discussion with the biggest rigs. That is something to take seriously. You can't assume you can load of a huge rig with people, gear, food, and a tank full of fresh water and go in a safe manner.
Older rigs are most concerning, ones made before 2008 for as mentioned above, they handle less weight. You will have a much better chance staying within the chassis limits with a shorter rig in the 28 foot length without slide outs. Each slide out adds 400 to 600 pounds. some more yet. When you hit 30 feet and slide outs, you really want to be looking at a Super-C with a real truck chassis, or a class A.
The sweet spot to be with any rig when loaded up on a trip considering people, gear, food, fresh water, and towing, is about 1000 pounds under the max chassis load rating. This way if you pick up a few unexpected guests along the way, you can still rest easy. If you have too much margin, say 2000-3000 pounds or more, then the ride gets compromised, very stiff with your house, contents, and family shaken into pieces.
Those are my thoughts about it, not necessarily everyone's thoughts.
