I don't know how casual you want the bag to appear....assuming that vacation = mostly casual, here's my thoughts -
The Chelsea tote (except for the inlaid C ones) look very business-like to me. Also, they have a breakaway zipper, which many people find inconvenient and might be a worry security-wise.
The Kristen totes are lovely and dress up or down but I would personally find them a little heavy for a vacation bag. Not sure how much you plan on carrying with you but I wouldn't find that bag that comfortable touring around vacation spots.
My suggestion is one of the Poppy Glam Totes. They come in a zillion different patterns, and there's a really cute whipstitch one out for Spring, and i do think I saw a turquoise leather one too. The fabric ones are super lightweight, and hold a TONNNNNNNNNNNN of stuff. I think it's a bag that can work with anyone's wardrobe, depending on the pattern/leather.
Good luck and have a great time!