I spent a couple hours today.
I bought some thin black Evergreen plastic, and covered it with spray adhesive. Then I took some old Right of Way switches and mounted them to the sheet in order to stabilize them. These two will form the crossover in the third photo.
I got the second curve finished, three more sections of track. Tomorrow the fun really begins. Next comes the last curve and all those switches.
These can be a little tricky with all their feeders, but once they're down, it's smooth sailing with straight track all the way down.
I ordered a double slip on Saturday, so I'll have to work down to the other end, then start working back with the yard tracks while I wait.