We last went in 2015 and I seem to remember that we got lucky and there was some sort of GR that was accessible while we were waiting in line outside MK for RD, We are going in October and I would hate to miss precious time right after we enter with RD to wait in line at GR. I guess the other option is just to RD and then when you have a lull in your day and crowds are larger at attractions, head over to GR.