Ride a bus (from Cubao, Pasay or Caloocan) bound to Iba or Sta. Cruz, Zambales. These buses will pass through the town of San Felipe. Just tell the driver to drop you off in San Felipe, upon reaching San Felipe take a tricycle that will take you directly to Sitio Liwliwa. Just tell the driver your resort name so they can directly take you there.
If you will not be able to catch a bus bound to either Iba or Sta. Cruz, you can take a bus bound to Olongapo. From Olongapo take another bus going to Sta. Cruz or Iba and just tell the driver to drop you off in San Felipe. From there, take a tricycle that will take you directly on your resort in Liwliwa.
In our case, we took a bus from Victory Liner Cubao to San Felipe for P530 and tricycle ride from San Felipe town proper to Liwliwa costs us P40 each.