My goal is to try and make the yard look under maintained with lots of dirt instead of fresh ballast.
I know actual dirt would have probably been the best choice, but right now it's buried under a decent blanket of snow and I didn't feel like digging any up. So I turned Woodland Scenics ground foam and Grout.
As mentioned before, I chose not fill the space between the tracks with solid ballast. I intentionally left some painted plywood showing through and planned to cover this with my "Dirt" and leave patches of ballast showing through.
After a little experimenting, I wound up mixing Woodland Scenics Fine Earth ground foam with equal amounts (approximately 50/50) of a Mocha (or an Earth colored) grout. This gave me the ability to spread/sprinkle the mix into the scene a little easier. Trying to sift the grout can be a little tricky as it's so fine and can get go down pretty heavy. By mixing it with the foam it gives some body and a little more control.
I started off by brushing a 50/50 glue mix that I used for ballast in a random pattern around the ballast patches as well as up on the ballast next to the track. Then using my fingers, I grabbed a pinch and started spreading it around the ballast. You have to be a little careful here as the Grout can stain and discolor whatever it touches and can be hard to get off. A little is fine, but you don't want too much.
This is a little time consuming, and I suppose there is faster way, but it worked for me. Trying to get good pictures of this is turning out to be a little more challenging. The color never seems to come out quite right but in person it looks pretty good.
This is the base color of the yard, but I plan to add some greenery to it, being careful not to put too much on. I'll probably use more fine ground foam as well as using the static grass. Another thing I want to try is to make and use grass/weed tufts mixed in with everything else.
As for ballasting, this all I have left to do for now, a small stretch from the top crossing around to the two turnouts by the giant pair of scissors and the tracks in the engine facility.
Here's a close up of the two wood crossing I forgot to add. These were darkened using PanPastels, then I sealed them with TCP Flat paint to help resist the glue mixture when I applied the ballast.