Yeah; it's probably not ideal, but just use your best judgment. I've ridden the trail a few times by myself while Brian was off doing something else, but there are usually people in the area. On a Saturday morning, you likely won't be alone, so that's good.
You might post something to HMBA's forum that say "Hey, I'm a new rider and will be out there by myself tomorrow out of necessity. Is there anybody out there who might be willing to make a lap of Pine Loop with me?"
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher