The "Sespe" was actually known as "The Dinkey" for most of her operating life, and led a fairly interesting one at that. My great-grandfather was the master-mechanic for J.H. Chambers and later Lorane Valley, where the little #1 resided from 1925 until her sale to Chad O'Conner. Chambers operation ran out of Cottage Grove, Oregon from 1925 to 1951, and the Dinkey was used the first couple years on small work trains and as bull-cook around the mill. Once the line progressed a couple miles out of town, the little locomotive was no longer very useful.
She spent most of her time sitting cold in the Cottage Grove yards, where she was nearly destroyed by a mill fire in 1942. Only a swarm of men who literally pushed her out of the flames saved her. It was after this fire that she recieved her rather ugly home-made cab seen in many later pictures.
There are some reports that she worked out of Yoncalla or Drain (Oregon) in the teens, and that she was actually winched to the top of an incline at some point, where she drug logs up a mountain and then let them down the other side. After this job was done, she was left in the woods for an unknown amount of time. J.H. Chambers then bought her and sent a couple of men up to get her, and enough time had passed to require the men to build a road up to her location, then roll the locomotive down to their truck for the trip into Cottage Grove.
Hopefully that fills in a few gaps in her history. She's a cute little thing, thanks for posting the pictures!