At what point do you need a DOT# and a CDL?

[Bernie Cunningham]

What I would recommend is a Non Commercial Class A licence, non CDL.

I have one after taking the test with my own equipment, using a GVWR over 26K combined. Borrow one to get it done if ya must.
There is also a requirement for a GVWR of over 16K combined that also puts you into Class A, just pick where you need to be. More is better here.

Along with the Non Commercial Class A you can get an Air brake endorsement.

There's also a bunch of confusion with all of the huge motorhomes going down the road these days. Now you have retired folks driving with lot's of weight and air brakes and a driver that holds a class C who thinks they're legal, they're not ! This is where the 16K thing came along years ago but that could be obsolete by now.