Nice shots! I haven't tried following it yet, but I may, especially this fall. Query... is there someplace for them to turn it around when it gets to those communities, or do they just put it in reverse and back it up all the way to Chehalis?
You're welcome. That's a sister railroad to the one I work on up at Mt Rainier, and we did the initial restoration on the engine. Harold Borovec, the driving force behind the operation, is a long time friend of mine. So I visit there on a regular basis.
There's no "community" to speak of at either place. Curtis and Ruth are pretty much the same place. They say they go to Ruth since they cross the large bridge over the South Fork of the Chehalis but stop short of crossing the road into the large open area that is Curtis. Milburn is just a dot on the map, near the intersection of Clinton and Spooner Road.
The line from Chehalis to Milburn is best for chasing the train. Check Google maps and you'll find the back roads you need to use to follow the tracks. The line from Milburn to Ruth is more scenic, as it follows the river, but it's tough from a photography point of view. Dense woods most places and you can't really get a nice shot of the river. The large bridge is nice, and they stop the train on it, so you have plenty of time. Unfortunately, the road bridge is on the east side of the railroad bridge, and they go out there on the evening runs, so it's usually pretty backlit. The last time I visited I had plans to shoot the train on the bridge with my drone, but the drone decided it wanted the day off.
They have no way to turn the train. So, what they do is "run around", putting the engine on the back of the train for the trip back. That can be handy if you go to Milburn, since you can see it from the road, and they stop the train for a bit giving you a chance to get photos of the crew at work.
Once the put the engine on the back, it looks like it does in your photo, with the front of the engine coupled to the last car. It's a 2-8-2 for my train geek friends, so it doesn't "care" which way it's going, they track fine in either direction. Built for logging, that's how it ran it's entire career, spending about half the time running backwards. It works well either way, and going backward you have a better view from the cab than you do going forwards, as well as having a nice cool breeze coming in.