Here we have a 750' climb on a severely eroded road/trail for mountain bike. A leaf strewn coverage could give you the illusion that the surface is rideable, while it might not be so. Falling directly on rocks beneath leaves will break the illusion with more clarity than you might want. Care must be taken. More than likely you will be walking some sections. Walking is mountain biking too!
Under recent rainfalls, the first water crossing could result in both shoes full of water. Other water crossings will require getting off the bike and portaging over proto-bridges/rocks.
Pay attention to the trail markers; School Mtn Rd has white markers tagged with Fahnestock SP.
The reverse direction is a very good descent for the skilled mtn biker. You will not be at the highest point at East Mtn Road, but will need to crest the ridge and follow it before it goes down with an attitude. Once again, be mindful of dangers: rocks and eroded surfaces might or might not be obvious, but will surely be in the path.
Combine this with the hardpack of East Mtn Rd going east, then a right up Long Hill Rd, Hortontown Rd, up Miller Hill Rd, go knock yourself out.