Ok, here's the reality. We pulled up to the gate at Herald Provincial Park at 11:08 and learned that the gate is closed and locked at 11:00. How about that?
So, since we towed our hotel along with us, we found a quiet place off the road and slept soundly anyway.
In the back parking lot of the Salmon Arm Best Western. Right next to an RV for sale, and just through the trees from the busy railroad.
When you're tired you can sleep through anything.