Now I will trow you a curve. Just something to think about. I started out with a plan on paper then I built the frame for my layout, no top. Used cardboard from appliance boxes to cover it. Drew the track on the cardboard useing chalk box for straight, string and nail for curves. Took my time got the track where I wanted it. I also put a slight curve in all of my straight track because straight is very hard to do. drew the roads and where to put buildings. Then I cut out the track plan from the cardboard. Used that for a template to cut out plywood. I then used 1X4 wood to make risers which I srewed to frame work where the cardboard was cut out, raiseing it 4 inches. Placed the cut out plywood onto the risers and srewed it in place . This gave me the option of haveing scenery below track level or above it. It takes a little time & planning but I like the results. If intrestd and need more info let me know.
Les