A car is a must
To get anywhere around Nayarit, you need a car. We rented one from Hertz near the PV airport. Beware - cars in Mexico are not like cars in the US. Oh sure, they are the same make, but there sure don't drive the same. We had a Ford Focus and it didn't even have enough spunk to get four of us up a hill. Every time we came to the hill that led up to our house, three of us would have to get out and walk up. I'd suggest a 4 wheel drive, but they are hard to come by in Puerto Vallarta.