For a flat overhead view, I am drawing it in MS Paint (one pixel = one stud), and as I go, I build each 48 stud by 48 stud section in LEGO digital designer. I am incorporating a set here and there, but the majority of it comes out of this crazy, creative mind of mine. One end of it has part of a city, and it will slowly end up in a remote area at the other end with an abandoned town complete with an abandoned rail line and some minifigures exploring it. There will also be a coal mining operation somewhere with its own rail stop, and a small town nearby. I have designed a passenger train that will run around the layout, along with a few different freight trains. So far I have only incorporated part of one set (a pizza shop, I will have to get back to you on the set number it is from), but have based some of my ideas off of others. The only thing i havent figured out in digital designer is how to give my railroad tracks a slight incline, but i will get it done. I have a long way to go before I start actually building, but I do have an “experimentation table” to make sure certain things work and will clear around curves and things of that nature. Now if only I could find my flash drive that has some of my files on it…