Haircut. Before you leave, get a good haircut. This will make your hair easier to maintain while traveling. If you're going for an extended trip, consider a short low matience cut that will look good with minimum care.
Maintain : Hats are great for sheltering your hair from the UV rays . Take along a conditioning treatment and use it as much as possible. I put it on after swimming and always keep it in my bag.
Don't Worry About It. If you're traveling for fun, don't think too much about your hair. Just relax and go with it -- the people you meet are probably far less concerned about your hair than you are.