I love my trips with my girls. My best advice is to just follow her lead. Make the time all about her and what she wants -- within reason, of course. We've done many of the things mentioned here, and my girls have not been harmed in any way whatsoever for having ice cream for dinner occassionally. We have had great fun playing in the rain and just playing in the pool.
Seriously, the thing that matters most is that she have your undivided attention for a few days. I think that is why everything is more fun on vacation -- because all the things that normally HAVE to get done like housework, cooking, errands, etc, aren't there to distract us.
Have a great time.