As I somewhat expected, the situation seems to have resolved itself. The tenants dad paid for her to stay in a hotel for a week, and the boyfriend (hopefully ex now) will move out by the weekend so that can go back on Sunday.
I know it sounds like she's a problem tenant from this story, but overall she is pretty good. Not too needy, but does let us know when stuff breaks or she has a legitimate complaint. Usually pays rent a little late but always communicates way ahead of time and does her best to pay a majority on time, with just a couple hundred that she will pay at her next paycheck. I just look at it like she pays biweekly. She's mentioned the boyfriend a few times and I never had a great impression of him. I hope things work out for her and I don't have to deal with anything like this again.
Thanks for everyone's input. I was most worried about squattor's rights and him refusing to leave even if I evicted him or both of them.