After endless fiddling with SCARM I finally settled on a design and have built it out. I decided to add an elevated return loop on top of the tunnels to add some interest. It's a 4% grade which definitely requires some attention when coming down off the plateau though my 6 year old daughter hasn't derailed it yet (knock on wood). It's a fun layout with lots of variety but only two remote switches and two manual switches (the switch for the elevated loop is manual). Now on to landscaping.... 
