My travels to Costa Rica have included many places, except the Pacific Coast....cannot comment on luxury travel as I was lucky enough to have a local American friend drive me all over in his own car. Using San Jose as a starting point, we drove to Fortuna, a very cool town, along the way passing small towns of Zarcero (awesome tropical topiary gardens), San Ramon, San Carlos.
A must see is Tabacon Hot Springs:
www.tabacon.com. Awesome thermal pools and waterfalls. Eye candy scale was a 10/10. I believe they have a resort there, with spa, etc. I never even took advantage of their spa facilities, as the hot springs were amazing. Remeber sliding down a natural slide into some hot springs and having a grand time! Great bar, restaurant, pool.
My friend lives on the Caribbean side, so we quickly drove through Limon (scary and ugly) down to Punta Uva and Puerto Viejo.
I heard from many travelers that Tortugeuro is very nice, lots of eco tourism and nature, wildlife, giant turtle nesting grounds. Would like to see that someday.
Enjoy!
Arenal Lake and volcano