If you're competitive, there is a Strava segment, hence the "challenge" in the name.
The route starts at the Marjory Swope parking lot on Long Pond Rd. From the trailhead, stay right at the first fork and immediately start climbing. The first half mile or so is a roller coaster until you reach the Penacook Pond Overlook where you can stop and relax or just keep chugging along. The view is quite nice, but this is a challenge, so I recommend checking it out after you finish the run.
From there, following a slight climb, there is a welcome descent leading to the connector trail that will bring you to Carter Hill and the West End Farm Trail
. There are some technical spots on the descent before you reach the small footbridge at the bottom. After crossing the bridge, there will be another fork... again, stay right (you'll come down the path on the left later on the return). The trail begins to undulate again after the fork with varying degrees of steepness and technicality. At the top, it's just a short descent down to District 5 Rd. Take a hard left, follow the road for about 200 meters, and make a right onto the trail again.
After a few small bridges, you'll begin a steady climb on the widest, least technical path of the trail. From the road, it's about a mile until the next turn onto the West End Farm Trail
(WEFT) on the left at roughly mile 2.7. The beginning of the WEFT is non-technical, but that will change fairly quickly. Keep an eye out for the trail marker on the right around mile 3.2. Here is where the fun/difficulty level goes through the roof, relatively speaking. The rocks and roots are everywhere so keep your eyes down and stay light on your feet for the next half mile. From there, the trail clears up and smooths out until you get to the next road crossing at the other end of District 5.
Stay left on District 5, then make an immediate right onto the gated dirt road. This is the only section where you can comfortably go more than 2 people wide, so if you're in a group, get your chatting in now, because it's going to narrow quickly and there will be more climbing.
At the end of the dirt road, take the left by the rock wall just before the open field (I missed it on my first run). It is singletrack for a short section until you cross and follow the rock wall back into the woods. After a short downhill section, take a left onto the connector trail leading back to Marjory Swope Park. There will be a fair amount of climbing from here on out. At about mile 5.6, you'll start the descent leading to the first foot bridge. From there, it will be simply backtracking to the parking lot. Stay left at all forks until you reach the overlook and eventually the parking lot.