Anything under 26,000 lbs gvwr and without true air brakes does not require a CDL according to federal DOT. Some states such as California have tightened their state laws.
Certain states, such as Nevada, have enacted towing restrictions on everyone (not just Deuce owners). If you pull a heavy fifth-wheel RV or any heavy GCWR trailer you have to get special endorsements on your regular class C license. In Nevada it's called J & R endorsements.
So I bit the bullet and am now training for my CDL A. It's just easier than trying to explain an R or J endorsement to an out-of-state trooper. When I took my written test at the DMV there were several RV owners who were doing similar. And they weren't too pleased about it either.
Apparently, Nevada seems to think that a fifth-wheel or any large trailer is very, very dangerous and needs special edorsement (read DMV money and ticket revenue). I would love to see the accident statistics showing the justification for this. With all the retirees with motorhomes and travel trailers in Las Vegas, I think the State's motives are financial, not safety.
So Nevada Deuce owners should consider getting their CDL's because the GVWR of a Deuce is 23.000 lbs. That means towing anything heavier than a 3,000 lb trailer (which an M105 is empty) will require special endorsements.