Just for clarity. The Secret lagoon is hardly a spa, and certainly not fancy. It's quaint and rustic - just a wooden building with changing rooms and a big open pool - very simple, and for me it was utterly perfect. We stopped as part of a day-long tour, so the driving time didn't factor in, but, yes, it is a trek. There were many (I'd say mostly) locals, with a few tourists who were welcomed.