The follwing is JMHO.
I hope this is OK and proper to do here. The following are just some humble thoughts/opinions/ideas in time-line form based on what has been released by LE and speculated about here from information from first-hand or more-hand accounts. I realize that there are many holes in this scenario, but then there are many holes in the information we have. I do this with some hesitation since I am new to this and don't want to take up forum space unnecessarily, but maybe there will be a thought or two that has not been considered yet.
3:01 - 3:40 PM Tuesday
1. MC leaves beauty school at 3:01 PM.
2. LE seems to think that there is reason to believe that she was at the park/boat launch area by asking if anyone saw her or her car there between 3 and 5 PM.
3. Meets male friend there or somewhere else and they drive around (speculation).
4. At some point gets her car washed at drive-thru car wash with male companion (based, I believe, on first-hand account reported here of MC getting her car washed with a male companion).
5. MC drops off companion, possibly back at park/boat launch area.
6. At 3:40 PM MC texts bf and says "Hey," and he responds and says "Hey." Why now? Because she will be driving home to her father's house miles away and does not want to text while she is driving, but still wants to check in with bf. (Speculation)
3:40 - 5:42 PM Tuesday
7. MC runs some errands before leaving for Orondo where she is expected at her father's home for supper (supper time unknown). My understanding is that Orondo is about a 30 minute drive from Wenatchee. MC sounds like the kind of person who would want to be on time, based on accounts that she was a responsible person.
8. She decides to stop somewhere, or is distracted by something, or detours to meet someone close to her at a predetermined time and place. Is there a rest area, turn out, scenic stop or place where one might stop between Wenatchee and Orondo?
9. She is abducted by a stranger who is very familiar with the area and taken to an unknown location, OR she is overtaken by someone close to her at the location they agreed to meet.
10. After MC is taken the perp discovers MC's cell phone and removes the battery from the phone; last ping is at 5:42 PM.
Sometime after 5:42 PM Tuesday . . .
11. Around 5:42 PM MC is killed at another crime scene, but not in the car, before the car is abandoned. Perp begins to panic.
12. The car is driven by perp and/or accomplice up Pitcher Canyon road. He/she/they stop before pavement ends out of fear they may get stuck or run into problems on a more primitive dirt road.
13. Perp abandons car sometime around 7:00 PM.
14. Perp either meets an accomplice for a ride back to unknown location, walks, or removes a bike out of the trunk for the ride back.
15. Once the homicide has taken place and the car abandoned, the panicked perp can collect his/her/their thoughts and find a suitable location to dispose of the remains.
16. Tuesday night/Wednesday morning, sometime before Saturday morning, the body is prepared and placed at the CB location where it is found just after noon on Saturday.
This scenario depicts the terrible act(s) happening somewhat quickly, the first night or so. It also assumes that the perp(s) know the area very well, OR, if not a local, a predator who has gone to great lengths to have background information and was just waiting for the most opportune victim.
Please pick away at the thoughts; they are presented just to stimulate more thinking.
And remember they are JMHO.