Quote from @Nathan Gesner:
Stop expecting her to respond.
Post a notice on her door and take a picture of it for evidence. Be sure to include instructions for turning in keys, notifying you that she's out, etc. I also recommend explaining what the penalty will be if she's not out as scheduled. Wait until the move-out date and confirm she's gone, then handle turnover like normal. If she's still there, institute your holdover policy.
I like this too - it's very definitive which matches my work ethic. I suppose my question on this is: Is her simple statement (which came in a text, btw) to me of "I'm moving out," enough for me to take this kind of action?
couple of bullet points to bring up:
* she's on M2M
* I told her on 12/7 of the new rent which would apply to a new Jan. 1 effective lease, this is when I got the "I'm moving out" message
* Sent her the move-out letter on 12/11, with options for her to either be moved out by 12/31 (she's fully paid up for month of December) or by 1/11 (30 days from date of notice) and pay a pro-rated rent based on her CURRENT rent amount. her choice, either is fine with me.
With all that said, I'd love to do as you mentioned and post a notice on her door.