One thing the layout needs in large numbers (besides coal hoppers) is trees. Fortunately, N Scalers in Northern Virginia have developed a great way to represent the lush green foliage of the Alleghenies in spring and summer.
Woodland Scenics Foliage Clusters are the key. First step is to spend several evenings in front of the TV tearing the clusters into N scale treetops. Roughly-shaped spheroids (think a fuzzy green football) about 1" to 2" across are about right.
There are several means of attaching the clusters to the mountainside. I used to use hot glue but have found that clear caulk is easier to work with. It doesn't get hot or leave strings behind. Spread about a square foot's worth of caulk and attach the foam. The caulk is sufficiently tacky that the "trees" will stay on even an almost vertical surface. If not, hot glue is a backup method.
The first couple acres of forest have been planted near Horseshoe Curve. Many more are on the way.
The purpose of this site is to share progress on the N Scale Model Railroad Layout that is being built in my basement with the help of some great friends and model railroaders. Comments on techniques we're using are welcome as are questions and critiques.