If you want to keep your layout simple (and inexpensive), you can stack about 10-14" of styrofoam diagonally across the center of the layout, giving it a viewing break, and dividing the layout in two halves. Half one can have a small siding and small coal mine, good for 3-4 small hopper cars. the coal mine can extend from the styrofoam to simulate a coal mine. A small siding on the opposite side of the layout to simulate a dock with perhaps a small ship docked to take on the coal loads. If you want some kind of military activity on the dock side of your layout, you can get 2-3 scale models of LST's, and you can call it a Naval Reserve base.