B&A is a great trail. My own real complaint is that there is a lot of stopping and starting (at least to me, cause I actually stop at the signs unlike a number of the riders I see). The B&A trail crosses a lot of side streets in Glen Burnie, but once you get near Marley Station you have a pretty good ride with few stops until you get near Severna park when you hit a lot stops again for neighborhoods and the downtown severna park area. After that there are a few more stops for side streets but not many. Be sure to stop because there are a few spots that have blind spots for the trail and traffic on the side roads tends to fly faster than the speed limit.
If you want to stretch the legs of the bike, after you cross the bridge over route 100 from marley station there is a really nice straightaway, slightly uphill heading south towards annapolis, that you can sprint on. I only do that when there really isn't anyone around.
BWI trail is also very nice, I regularly ride that as it is a short ride from my house to it.