My cousin booked an amazing wedding at the adventure resort Costa Azul, in the tiny Mexican village of San Francisco about a half hour north of Puerto Vallarta. The town was perfect: cobblestone streets, a beach known for its surfing, turtle releases at sunset. There was only one catch: Costa Azul wasn’t a big resort and it was booked solid within hours of her save-the-date e-mail. For guests still looking for a place to stay, there were only a couple other small hotel options in town and they were rapidly filling up.