Actually, you'd be surprised how many decisions are spontaneous. Things just come up during construction. A lot of times, I'll take a break from that project, mull it over for a couple days and work on other things til I figure it out.
The lower deck had a very firm plan, which I had drawn out and followed very closely. The upper deck had a vague partial plan on paper, but as the benchwork got built, the details started falling into place. I'm quite pleased with the way it has all turned out. I have no plans to add, subtract or realign any tracks. I might fix some elevation issues, by lowering some risers, but that's pretty minor stuff. Still thinking about that one. See how it works?
Now the small hidden yard was totally seat of the pants, and was maybe the best idea I've had from a track planning perspective. It adds so many operational possibilities.
As far as memorizing everything, it really helps that I have chosen to model the real world, then I "cheat" on top of that by having it all be local, within a 40 mile radius. Google Earth brings much of the information right to my computer, and takes me places I can't get access to. There are also a lot of things that if I need photos for specific structures or anything else, I can just hop in the car with my camera and go get them.
BTW, asking a zillion questions would not be pestering me, it's really what I live for. We do have a guest room, but there are also plenty of hotels in a 10 mile radius.
