It's also 40+'
https://dmv.ny.gov/about-dmv/chapter-1-driver-licenses
Personal Use Vehicle (Rental, Recreational Vehicle) or “R” endorsement - The Personal Use Vehicle “R” endorsement is required for operation of recreational and/or rental vehicles used to transport personal household goods when the vehicle is over 26,000 pounds (11,794 kg.) GVWR and/or forty (40) feet in length. This endorsement is available to Class D and E license drivers.
To get an “R” endorsement: Submit a completed Application for Driver License or ID Card (MV-44) to a state or county motor vehicle office; pay a permit fee, which is valid for a maximum of two road tests; and pass a road test in the size and type of vehicle you will drive. No written test is required. For the road test, a driver who is at least 21 years old, with a license valid for the vehicle you will drive during the test, must accompany you. (e.g., a driver license with an “R” endorsement or the correct Commercial Driver License). The road test will take approximately 15 minutes and will include turns, intersections and backing the vehicle to the curb. When you pass the road test, you must go to a motor vehicle office and pay the required fee to complete the license amendment process.