Hey Matt,
I didn’t read all the post above but I have been doing forest for the last year and half so let me tell you what I have learned.
1. I have found that walk-mesh cutters are not that big of deal. This can be done real fast if you just make yourself a pallet of about three walk-mesh cutter squares, small med and large respectfully. Small squares for small trees and so on. Click on the cutter square you want and then just copy/past your walk-mesh square. Now you have a stamp for cutting out trees. I can do about hundred trees in just a couple of minutes this way.
2. A trick for density is the ‘Leaf Canopy 02’ placeable. This is nothing more than a wall of vegetation great for that last outer ring of trees around your forested area. Gives the forest that dark impassable look.
3. As far as fade goes I would only turn off the fade on your largest trees. This can give the area a forest feel without interrupting game play.
4. Don’t be afraid to paint down a few crude paths. Remember animals make trails as well as human races.
That’s all I have off the top of my head. Good luck and BTW really jealous of your screen shots.
alupinu