I ran away from home to stay with my dad when I was about 11 and I was home within a couple of weeks. I think I cramped my Dad's lifestyle and it wasn't so much fun staying with him full time.

I think you are doing the right thing by letting her know that if she does go then you will be re-establishing the ground rules. I think both she and your ex won't be too happy living together in a caravan full time with each other due to space and lack of privacy. When she does ask to come home you will be able to give her the run down of what is expected of her to be able to do that and hopefully she will stop acting like such a spoilt brat.

As tali said though you need to talk to your ex about this so that she doesn't just go back and forth when she doesn't like something that either of you have done. Good luck!!