Ranger Creek State Airport (21W) in Greenwater, Washington, USA, is a very spectacular airport. It is located in a curved valley at 2700' close to Mount Rainier and the entire 2900' runway is surrounded by trees. The airport has the following remark: "Watch for pedestrians, vehicles, and animals on runway" :-) See airport description and photo and pilot information.
Unfortunately the trees surrounding the runway is not that well represented in the standard scenery which makes the airport easier than in the real-world. The payware add-on Georender1 from Lago (for FS2002/FS2004) enhances the airport scenery (as on the tour picture).