It does remain possible KR ran away or is taking some time away.
We haven't really discussed it as possible, at least not that I have seen, since she seems to have a good relationship with her mom and has other strong social ties.
We do know she has income, she has a vehicle, and while she was academically motivated to graduate high school early, she is also out drinking and partying. Completely within the norm for teens, and I'm not judging by any stretch, only agreeing there is a slim chance something like what you have posted could be going on.
Her friends may not have any knowledge, IF this was the scenario.
Teens with no apparent reason to do so, DO sometimes leave home, and she did have opportunities to meet people her family and friends may not have known about.