I'm an Anderson Cub
I think she was abducted. Possibly someone who lives out in Mountain Gate/Shasta Lake City and took Old Oregon Trail to get to I-5 to go into town. I think they took note of what time they saw her jogging and planned out their abduction. To me it seems like they had some way to subdue her and took her in an area where there were no cameras. I do think it's possible that it's an RSO.
I am also on the fence about her leaving on her own. I have several friends who went to school with Keith and Sherri, and all of them have stated that they do not think she would have left on her own, and believe she has been taken.
I am leaning more towards an abduction because I don't see how she could leave on her own with no car, without any help, or anyone seeing her in the days since her disappearance. This case seriously has me baffled.