One of our favorite places ever is Cuixmala. We went there to do a story for Cookie Magazine--it was a piece about Cuixmala and their sister property, the Hacienda de San Antonio. Both are magical, and worth a trip, but since they are a three hour drive away from each other, it's not necessary to do them on the same trip. Cuixmala isn't for a family that wants a kids club, or a resort kind of vibe. It's also not for the family with twin toddlers--lots of stairs, a drive to get to the beach, and no baby-proofing--unless they are super patient, mavericks, or Swedish. It's such a large property (2000 acres is Cuixmala, but it's within a 25,000 acre federally protected preserve), it feels like you got invited to some very wealthy friend's estate (it actually was billionaire Sir James Goldsmith's private estate--but now the family has opened it up to guests). You have several options for accommodations: There are villas for rent, which are good if you go with a large family, and want to have full staff and your own pool.
The food is really simple, homemade Mexican--which is such a relief since so many high-end properties always want to make the food more complicated than it needs to be. More than 80% of the food comes from their own organic farms--they have farms at Cuixmala, and at the Hacienda (a coffee plantation as well), so even your coffee is super local.
Clara loved riding horses there, and going on lagoon boat rides at the end of the day, when all the birds are out. We even got to watch the sea turtles hatch--and they let Clara hold an egg and one hatched in her hand!
The best beach we went to was a 10 minute drive up the road, and it was probably the most special beach I have ever been on in Mexico. It was completely private, and at the end of a long dirt road. But when we pulled up, there was a lunch being prepared for us, there were hammocks slung, and beach chaises put out. And because it was developed by and for Sir Goldsmith, of course, there is a full bathroom at this very special and remote spot.