Well since this is the Mike's forum, did you think about turning your siding into an elevated climb to the second level? Based on your pictures I did a quick mock-up. It has a 5% climb so steep, but not impossible. The SCARM file needs the hills and bridge supports cleaned up. You could also move the route over so that the loop rounds the mountain. It will be edge to edge but not a lot taller and will fit into your existing scenery. That should keep the Mrs. happy.
