Jim you are correct. We made a reservation for a campsite at the Douglas Fir Campground in Mt. Baker-Snoqualmie National Forest for our first night out from Chilliwack, BC. (after being exported ??). It is 24 miles from Sumas, WA. and we wanted to have a couple days for shakedown before departing the area. The reservation was through Recreation.gov which handles the reservations for US federal areas. Found in their FAQ'S:
Q. Does the vehicle length include the trailer and the tow vehicle?
A. The vehicle length listed on the website is only the length of the actual camping vehicle. It does not include the tow vehicle.
"Never argue with an idiot. They only bring you down to their level and beat you with experience." George Carlin