The Main Line

Between Plummer Jct and St Maries, the STMA operates a 19 mile mainline. This is former MILW trackage, and is very scenic.
We'll go from St Maries towards Plummer Jct, chronicling key scenic elements. (This video is also a great tool to follow the main http://www.youtube.com/watch?v=MIbissaC8W4&list=PLDA6213C4DA9FD7B4&index=6&feature=plpp_video)
http://www.nicdoncaster.com/PNW/stmariesp.htm This site also has some good shots, including one of the tunnel portals.
LEAVING St Maries, the line winds through some residential areas, and then the first major scenic feature is this causeway http://binged.it/MoaCEN (it's difficult to see, but it's towards the bottom of the page). For a great look, click the video above and fast-forward to the 5 minute mark.
The rails then follow the river. Towards the end of that stretch, there is a small passing siding and then a random spur, before the rails turn about 90 degrees and go through a short tunnel and then onto the Benewah Lake Viaduct http://binged.it/Mobd9F or at the 5:53 mark in the video.
The tracks continue to follow the water, and then a road joins, which the rails cross, then plunge into the forest, but still roughly follow the river. They then cross the same road and a small valley on an impressive bridge. http://binged.it/LqOc0x
I can only assume this is the Peedee Creek Trestle, at 6:32 in the video. Just past the bridge it seems there is a small MOW siding.
Now the rails really dive into the woods and follow a twisting route through the trees, probably to maintain a reasonable grade. A road joins the rails for the final bit of run to Plummer Jct.