Take the bikes, it's better than running! Plus, it's a great reason to get out of a crowded house and get fresh air.
The trail is fun enough, but I found about the time you get to a moderate pace the trail dumps you into sharp corners at the bottom of the next rise. momentum is killed and it feels more uphill (very easy grades, though). I'm not the strongest rider, so it's not my first preference. On the upside it's probably a better leg work out than TRTP.
It is marked okay, make sure to keep taking 'rights'. The beginner loop starts on the right and comes back to the middle of the entrance. The intermediate starts in the middle and ends at left of the entrance.