I'm the sole heir and executor of the estate. The family friend who lives near where Mom lived is the alternative executor and has told me she will help in every way that she can.
Based on what I know now, it does not look like I will have to rush down to California (which is good due to the weather; I would have taken the train and rented a car in Sacramento if necessary). I've spent this evening making many, many calls, talking to the deputy sheriff, my sister, the family friend, the brother of the man with whom Mom had been living (who owned the property in which Mom had been living), and so forth.
Lisa has been extremely supportive, and I'm very grateful for that.
I've been having to do a whole lot of "adulting" for my family, and this just ramps it up a notch. But I think my grandparents who raised me would be happy with how I'm handling it.