I-Sly
You have a great idea. I went sly two summers ago (I was facing the same problem and at the same age) before studying abroad in Germany for the summer. Sly is GREAT for traveling. Trains, Planes and Automobiles, any way you do it it's better not to hassle with worrying about how your hair looks. And hitting the beach? Don't forget the sunblock but sly is great for swimming.
Buzz it down first, then shave when you're ready.