You've got a lot on your plate...but you are strong and you know what you need to do.
So, that explains some of what is going on in your D20's head, i.e., the texting w/the group at college. I'm going to ask you a question and I want you to think about it for a while. Do you think your daughter sees this college as a place to run away to? Do you think she wants to go to school there now because of the fun and social activities w/the other students or do you think she honestly wants to get her degree at this time? If she seriously wants to learn, she can prove that to you, but most importantly to herself by working a job, paying off the $2500 loan and seriously considering taking one or two night courses until the fall semester and then she can look at where she's at in meeting her financial responsibilities and goals.
I had to laugh, but I was extremely proud of you, when she asked about her birth control pills for her acne. Doesn't she realize that she's an adult now and working a job. A job, no matter how important, is better than nothing. If she hates the dishwasher position, she can always look for something else while she continues to wash dishes.
I'm very concerned about her behavior. She has shown that she can be verbally and physically abusive and that's not good. Heather, I'm very worried about you and your youngest daughter being around her when she's acting out. Does she only act out like this when she doesn't get her way? Was she bulled as a child? There is something going on w/her that needs to be addressed by a professional. Unfortunately, you are too close to the issue and you can't help her. You can't fix something that you didn't break.
Set your boundaries and stick to them. If she needs acne medicine, she is earning some money and can purchase the medication herself. If she can go back to the college for a few days and spend money, she can also figure out how to pay for the necessities she needs to live. How is she planning to get there if the jeep needs work? Surely you aren't going to loan her the rental car?
Heather you've worked hard, you've earned the respect the you should have gotten many years ago and your daughter needs to learn to respect you. Stand your ground w/her. If she doesn't like it, she can leave. But, I can assure you, if she does leave, she'll be back because she can't make it on her own w/o you taking care of her.
Good luck!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.