Finally got out to Musterground Rd today (it just opened last Sunday) and it's a really pretty trail. A lot of it is directly next to the lake, so you're overlooking it while you're driving. It'll be especially nice, as far as views go, when the leaves drop.
They did a ton of maintenance on it over the summer so a lot of the trail has fresh gravel on it and you can tell that several spots have even been graded, assumedly to level out some heavily eroded sections. So it would be a good trail for a beginner-friendly ride, as it's not challenging. There's a handful of super steep sections, similar to Chestnut Mountain, but there's no shortage of traction.
As for camping, we saw a few good spots but none that would be big enough for a large group. But we didn't have time to go all the way to the end, so we'll get back out there soon to do the whole trail and see if we can find group camping out there. If there's not camping on the trail, we could always just run the trail during the day and then camp at Devil's Fork or Keowee-Toxaway.