On a recent trip, the campground was closed until about 6:00 pm
As I was heading towards the campground, a stream of cars passed me.
When I rolled in, a couple of people offered a place to pitch my tent. It didn't take much space, and allowed cars to fill all the designated spots (no bike specific camp sites).
Anyway, I met a couple of guys returning from a week long Cycle Oregon Tour. It sounded like fun, but not quite my style of adventure.