All Mexican airlines and major international airlines fly to Puerto Vallarta. In addition there are numerous US and CA charter airlines. At the airport you find all known reantal car agencies and Taxis. From near the airport there is also a local bus connection into Sayulita. Please inquire locally.
From Mexico City:
There is first class bus connection to Puerto Vallarta several times a day.
If you have your own car:
A fast but expensive toll highway connects Mexico City with Guadalajara and continues to Compostela. From here continue as below:
Heading South from the US border:
You come down through Mazatlan and Tepic heading to Puerto Vallarta. From Compostela take Mexico 200 ('Pacifico') . At km 123 which is about 40 km north of Vallarta, you see the sign pointing to Sayulita. After passing the village sign take the 1st road to the right. Follow it straight ahead until you see the Pacific Ocean: You are at Sayulita Trailer Park in front of the office!