According to Timm Muth in an article on Singletracks.com, the lower portion of Spencer Branch is "surprisingly smooth, with plenty of small rooty hops and creek crossings to keep it interesting."

Once you access the upper trails in this complex route, the singletrack gets steeper and more challenging. By Pisgah standards, these trails are still very approachable by intermediate riders—at least, intermediate riders with good fitness. Bear in mind that these trails are intermediate compared to other routes in Pisgah—root webs, rock gardens, and stream crossings abound, keeping the riding quite challenging.

Another factor helping to make this route approachable is how its split into two distinct halves. Since riders will return to the trailhead halfway through the ride, it's easy to cut this route in half—or even less.

Spencer Gap specifically has seen about half the trail rerouted into a more sustainable alignment. As a result, half of this segment is classic Pisgah tech and the other half is smooth, flowy, and filled with berms—the best of both worlds!

Sources: http://www.pisgahareasorba.org/2010/04/trace-ridge-spencer-branch-middle-fork-fletcher-creek-intermediate/ https://www.singletracks.com/blog/mtb-trails/love-newbies-8-easy-mtb-rides-western-north-carolina/3/ https://www.youtube.com/watch?v=4P-zRJiDeWA