I was in a similar situation with my ex. When we first started dating, we had a two week intermission because we were on Spring break. She went to her home town, and I went to mine. Texting is boring, so I didn't even bother with that. But Snapchat worked wonders. A lot easier to be creative, show attractive traits and keep her attention through it. But I would only try this given that you and her are both in the appropriate age range to be using Snapchat regularly. But to be honest, if she's as busy as you say she is, trying to Snapchat or text or do anything really all day will probably be a turn off or at the very least, a burden to her. So I would only send her one or two clever texts or snaps while she's gone. On the other hand, if there are periods of time where you know she'll be free, I bet she'd be more than happy to hear from you. I would take advantage of those
Other than that, I don't think there's too much in your control. It all depends on:
1. How good of an impression you've made thus far. How much time and other types of investment have you gotten from her?
2. In general, how much does she like you? If she likes you a lot, she'll probably be excited to continue seeing you when she gets back. If she was only "meh" about you, then there are no guarantees.
3. How much stimulation does she have at the beauty pageant. In particular, is she likely to meet another man there? If so, that too will make it harder for you.