If you take the bus there, make sure to check the times for the last bus. Bring snacks just in case you get hungry during restaurant off-hours.
June to November can be very hot and humid.
If you want to avoid crowds, go during the week. Check to see if there is a festival going on in San Pancho before you go.
Use public transportation (either use the bus round-trip or bus to Sayulita and then taxi to San Pancho) instead of using a taxi the whole way.