We are going the same time different ships.
Hey Carnival allows you to bring a bottle of wine per person on board. I'm just saying.
It seems most water taxis leave from Boca de Tomatlán.
Here is a link for Yelapa. http://www.yelapa.info/transport1.html
A roundtrip water taxi ride is 250 pesos.
This place looks interesting. I would send them an e-mail and see if they do day passes. Here information on getting to Majahuitas. http://www.differentworld.com/mexico...rta-Mexico.htm
It looks like Vallarta Adventures does a tour of Yelapa and Majahuitas for $50 per adult and $35 per child. That might be the way to go.
Here is a great article on Quimexto.