There's a ton of misinformation in this thread. For one thing, "Not for Hire" don't mean squat on the side of your rig. It just makes you look stupid.

My tank trucks at work that I operate are"not for hire" But yet they are hauling hazmat products everyday and are subject to all the rules. Been operating a small fleet of tanker and hazmat flatbeds(14) since 1984.

The length thing in a few states is nothing new. It was a big story on the NHRA tour like 10 years ago.

Your buddy got hasseled because he stood out. Broke down on the side of the road get's there attention.
I hope he didn't have decals on the outside of his MH stating 29000lbs, because that would make him commercial.

I don't believe you need a CDL license in California for a motorhome over 26000 lbs.

What's your buddys motorhome look like?

Also what is a "class B non com license"?