Design help for new layout - Model Railroader Magazine

Welcome.

First off, I think your approach to planning the layout is just fine.  Starting with simple table tops to maximize the footprint within the room is a good place to start.  If you start by designing the trackplan then building the benchwork to fit, you're going to introduce some benchwork construction complexities that might stall the actual layout building.

Having a rough sketch is essential, but you can also tweak and modify the layout plan by rearranging track on the table tops to see what looks good to your eye.

At first glance, I would eliminate the 18 inch access and just run the benchwork to the West wall, or make that ailse at least 24 inches if you have something special in mind.  As a rule, you should keep everything within 30 inches reach from where you might stand. Yes, that does matter.  Building access hatches to reach deep benchwork might not be suited for a beginner.

As far as scenes.  You obviously want what suits your interest, but many beginners try to put too many scenes into the given space, IMO.  The notion that you want both farm fields and a mountainous area with a coal mine suggests the transistion between the two might not look as realistic as you planned.  It helps to keep the theme of the layout confined to only a few things, so it has a level of consistency throughout.

Also, do not try to cram too many buildings and industries into a given space.  Look at some of the newer layouts on the web, and you'll notice a trend towards making industries larger, but fewer of them than what was the norm with some layout plans designed decades ago.  Again, a common theme to the layout helps here since larger buildings will tend to run together too much if there are too many of them.