>>>....(Side question: is there a way that, when a transition between sections approaches, a RealDrummer can "sense" it and do some kind of transitory fill or something non-routine?) ...>>>

This is what BiaB is good at.

Look for the letter A at the very beginning of any song. This is a part marker. One of the things it does is to warn the drummer to do a little fill before the downbeat of the measure whee the marker is. If you click on the letter, you can get the A variation to play, or the B variation.

Now click on any other bar number in the song. You will see that you can put an A or a B at any bar you want.

Now RIGHT-click at any bar and you will see you have a lot of control over how the fills work.

Flatfoot sez: Call me when 'Talent-in-a-Box' is ready to ship! -- [8{>

Got some tunes on You Tube:
http://www.youtube.com/user/flatfoot50
.
My BiaB lesson site:
http://jdwolfe0.wixsite.com/learnbiab