Updated 7/7/2019 (PM):
I think we are finally done with this segment. It's not perfect, but I've done what I can.
I started out by screwing the supporting table to the bottom of the Stone Arch's base. I did drill a hole for the wires, but it won't be big enough for all 6. I will end up running the wires along the floor of the arch out the back and disguising them with ground cover and trees.
The next step was to flip over the arch, place it in position and screw it down. The corner braces will keep it from moving.
Finally, I screwed down the sub-roadbed, making sure it dove-tailed correctly with the edge of the layout and the hatch.
Here's the mostly finished sub-roadbed piece. I still need to add vertical supports, but I'm tired. That's it for today.
Oh, and we did have a visitor (at least an attempt) to the layout today.
More when I know it. 
George
