Then wouldn't this be evident in a property owner search?
I'd think there would be MANY steps needed to move into a property ( condo, apt. or single family dwelling)- furniture to buy, utilities to either transfer or turn on- I know most cities have a single clearinghouse for all services now, food and other items to stock a kitchen to eat " at home", bedding, comfort and hobby items for a high-energy teen, and communication devices ( if she is not using her cell phone to make outgoing calls).
I guess it would be possible, but it seems like a lot of work mostly alone for such a small payoff. Most people confront time- sensitive legal issues. I'm sure the will has time limits which she might not want to ignore for her and her daughter's sake. IDK much about wills, just thinking about the situation.
Mostly, the weird thing to me is to not put her daughter back in school after spring break with no known explanation or reason if she was just " getting away". I'm pretty sure that schools have rules about attendances and absences. Also, I don't think ( while thinking in an " off the grid" way) that she had time to become a homeschooling parent. And would a girl in an exclusive private school want to be cooped up and homeschooled? I would have run away from home, seriously, and I just went to regular public HS.