The Bell Mountain trail and the Taum Sauk section of the Ozark Trail (both of which I hiked on this trip) were easily the best hiking I've experienced in Missouri.
Before I get into discussing the trail, I have to comment on the excellent Topo maps that were made available for free at the trail head. Very impressive and spot on.
For my hike, I started at the southern trail head off of MO-A, and took the full loop, going west down to Joe's Creek and back up around to the summit on the east side.
As much as I prefer loop hikes, I think if I was doing this over I would stick to the east side. Hike from MO-A to the summit and back. The west side of the loop (the Joe's Creek side) was ok, but the east side, and especially the summit, was spectacular. If you've got two cars I would reccommend you park one at the northern trailhead and then hike from the southern trail head, around the east side of the loop. I think that would be a great hike. In any case, don't miss the southern spur between MO-A and the loop. It's a small piece of the Ozark Trail and easily the most difficult part of this hike. The reward, however, is the best views of the hike. The southern vistas are wonderful.
One other really interesting point, for as long as it lasts, from the Bell Mountain peak you can see the dam breach that ruined Johnson Shut Ins State Park.