One problem with using 'fast food' places is their parking lots and entrances don't always lend themselves to highways coaches (heck, many don't lend themselves to passenger vehicles!) The Tim's at MR2 can be particularly egregious, as many of them are, especially in the summer. Also, people dropping off/waiting for arriving passengers fighting for space with restaurant and drive-thru traffic. I would assume the Commission has some kind of minimum standards for station access (i.e. clearances, sightlines, pedestrian conflict, no reversing, etc.)
The roadway down to the Huntsville train station, along with space to turn around, might also be problematic for highway coaches as it is currently configured.