From Quepos take a Bus to Uvita
From San Jose you have to option take the bus via Quepos or take the bus to San Isidro de Perez Zeledon and from there the bus to Uvita. The first option is longer, but a great drive next to the ocean. The Second one a shorter ride, and great view over a great mountain range.
From Palmar Norte and south of there, the bus to Dominical goes by Uvita, or the Uvita bus stop at the town.
Best way to get to Uvita from/to SJO airport is Easy Ride Shuttle Services they run shuttles twice a day in moderns vans, professional drivers, A/C they go thorugh the Cost and trips is just 3.5 hours a lot faster than regular Bus.
You can also fly into Palmar Sur via Sansa or Nature Air.
Or rent a car and drive your self.
