So if we assume Sasami is Amaterasu, then staying in her house is hiding in her cave. From what I've read both the mirror and the magatama were used in luring her out, so both Kagami and Tama will be needed, but we're still mising some essential ingredients. And her reaction to the outdoors was strong enough that I suspect a direct transcription of the myth won't be all we need to rescue Sasami from her "cave." Stepping out into the world was actively harmful to her somehow. There's too much symbolism going on here for me to write that off as mere hikikomori agoraphobia, either.
This show is deep. The problem is that I can't tell how much of that is due to the actual story and how much is due to someone being really high when they were making it.