Presumably she can start moving her stuff out whenever she wants. The only part you need to be there for is to do a final walk through and to sign the paperwork. Since you didn't take a deposit, you will likely need to sue her if you need to collect additional money, since she doesn't sound like she will be forthcoming with it.
"If Lodger told me it was none of my business and I could stay home all weekend waiting for her to leave, me accommodating her and her relatives schedule would stop and Lodger would be given a day and time. I presume that in the eyes of the law reasonableness works both ways"
I don't think you are being reasonable at all. You gave her notice to move out. A landlord doesn't get to tell you when you need to move unless that was in the initial contract, just when you need to be out by. If you want to be there, that's understandable, but you're going to need to work around her schedule.
Just as making her wait for the decision was teaching her a lesson, this is doing the same. As long as she's out by her last day, how she accomplishes this is really up to her. From a practical standpoint, what can you do if she doesn't tell you when she's planning on moving out, make her stay, not let her move out even though the deadline has past?