Mr Bill ,
What I like about this plan.
#1 wide enough curves.
#2 No straight edges on the fascia
#3 simple track plan
#4 plan for incorporating it into a larger project
#5 the intelligent use of masonite as a stiffener under the track (paint it on both sides before fastening it down to minimize dimensional instability due to moisture variations.
disadvantages I see so far. using the foam as a base can make scenery below the track problematic, unless you cut some of it away and splice underneath it. I like open grid bench work or L girder, with the roadbed well elevated above the benchwork to allow scenery below the grade. I am well aware that this makes for a heavy layout section, which will be less than ideal in a lot of situations.
I like the larger plan, looks good, congratulations on thinking small, with a plan to go big. It is good, also, to see someone else with an interest in the iron business, which is a sideline of my outfit which is over in the logging mining and industrial section.
Thanks for sharing.
Bill Nelson