My biggest recommendation would be don't miss the triangle, the trail you see on the maps seperated from the main park area up the the Northwest and under the street from the arboretum. To get there head west (towards 610) from the main trail heads, go under the two bridges (pedestrian and rail) cross the entrance to the arboretum and IMMEDIATELY bear left to go down into the storm sewer to cross under memorial drive and enter the triangle. Hang your first right, or your second right if you miss that and enjoy one of the more technical and least travelled trails in the park.