This loop just never gives up - there are no lulls in the ride - you are constantly either climbing up or tearing down the trail.
Be prepared to go over logs. I counted about 25 last time I rode this route. They range from shin high to waist high.
MASS Superseries has a yearly race here. The trails are very well kept even after multiple weather events.
I start from the very rear parking lot behind the school and located near the school bus depot. The trailhead is located in the back corner of the lot.