The problem with not securing the track to the platform is that it can move, even if the sections are zip-tied together. I would invest in a small package of black #6 panhead screws. That will keep the track on the platform, and the trains on the track! (And Rob is right, you need at least a 7" straight on either side of the Hellgate, and more is better. The MTH 305 Hellgate is slightly wider than the 300 and less likely to be a problem.)
Kirk