The average length doesn't matter, if you're too long. I've seen sites that could hold a semi pulling double and some that were too short for a Jeep Wrangler pulling a pop-up. Its more a matter of a space that's limited by an immovable object like a tree or the space between two roads. And that varies a lot.
I overnighted in a CG in Calgary, BC that had spots that were so long that they had full hookups at each end of every individual parking site. I've been asked the total length of my rig more than once.
That being said, 60ft. and towing a car will limit available spaces at almost any CG. There's no money in limiting the number of spaces in a CG to accommodate the rare rig that needs that much room.
Retired and visiting as much of this beautiful country as I can.
