Horse riding AND Mountain Biking are BANNED when snow is present. (They open the park up to Cross country skiing from the Hobart Parking area... ski rental and all)
This is one of the most challenging and fun sections of trail in Chapin. I had to break it out of the regular trail to give it the Intermediate/difficult rating because of the climbs and boulders/rocks on the trail. It is not something I would advise riding before you have walked because there are a lot of places where you can get thrown from your bike (look at the picture of the bloody knee).
You start (or finish) at the intersection of Lucky Stone Loop and Arbor Lane Trail
and climb the steep hill with water bars on it, follow the trail around to the left and you'll be greeted with a somewhat fall-line washed out rooty, exposed boulder section that is a hoot to climb or decend. It is a short section, but it makes Chapin a great ride.
There is a muddy section in the middle that could use some armoring, but I will have to approach the land manager about that sometime in the future.
At the "end" of the trail there is a 4' "ledge" that is a lot of fun to ride up and down, but make sure you remember to keep off the brakes and put your weight back in the seat!!