I enjoyed your pictures and explanations of your elevated layout at your "new" house. I will probably use the deck piers but 4x4 treated posts (when they become available) with wooden frame between posts. Like you, I've got the little pink flags around the yard marking the route.
I also enjoyed your video of Calico & Potomac RR. The Potomac must be for the western branch of the Potomac, eh?
I believe I might have met you once at Dan Stroka's house in Forest Hill, MD; possible?