A few years back I was buying a heavy tow vehicle (for a fifth wheel). The truck’s GVW rating was well above the threshold for needing a CDL, and I had a hard time getting a straight answer on whether I needed one or not. So I decided to go to the source. At the time I lived in Vermont, and I contacted the Vermont State Police to ask about this. Eventually I was connected with the sargent in charge of commercial enforcement, and he was delighted to explain the entire scenario. Apparently most states follow a national uniform commercial code (not sure of the correct name), and a few states - including Vermont - had their own laws around commercial enforcement. The way he explained it was that this all of these laws apply to COMMERCIAL USE ONLY. He told me - quite literally - that your grandmother could buy an 80,000 lbs 40 foot propane tractor / trailer and drive it anywhere she wanted as long as she was using for her own use. He told me that the uniform code would work like this, and that he was pretty sure it would work this way in other states as well. But he did indicate it was very possible to have a local police officer not understand this law. So - I went ahead driving my 34,000 GVCW vehicle without a CDL. I have heard that there are some new laws about driver’s license endorsements for larger RVs and motorhomes in Texas and California, but I don’t know anything about these. Hope this helps.