Jim, One of the issues is any trailer over 10k or a rig that totals over 26k brings into call the need for a CDL. What i have learned is that just because you have a CDL for any of these does not mean stoping at weighstations ect. for a non comercial venture. The problem is that the police in most states can't tell the difference which is why I run a log book even in my motorhome pulling my 10k trailer.

Check your state DOT information but also go to the Fed DOT information page. I keep all of the Federal information printed in my log book so I can educate a trooper if needed.