HO 6X8 "Doughnut" Style with central access

The desire here is for a bit of a yard and some industry switching in 6'X8' in HO with aisles on some sides and an access hole pop-up in the center. Since the benchwork was already done, the basic overall shape was set. From this thread: http://cs.trains.com/mrr/f/11/t/253428.aspx