I had a chance to take a nice long ride at Pine Haven on Sunday afternoon.
I finished cutting out the other length of fallen tree blocking the section of trail in the "back forty" of the park. I saw no other major obstructions.
There is a fallen tree blocking the trail. This is in a few miles, after the fifth(?) two-track crossing. At this point, there are TWO trail options. The option to the right is the trail that leads to where the tree had fallen. This is where most of the horse stuff was located. I had a little 8" pruning saw, and I managed to remove one section of the tree from the trail. However, the other end of the tree is still blocking a section of trail around the next turn. Here, the tree is about 12-13" in diameter, so I did not quite cut through that one all the way yet. If it's still there next week, I'll try to remove the rest of the tree.