Most of the dive shops in Costa are in Guanacaste Province. Doable by air in under an hour however have to wait 24 hours (?) after diving to fly back so don't get the Bends. Many nice places to stay up there though. If I had 6 nights the
first 2 would be in San Jose "getting my plumbing checked out" from muchas chicas, 2 days for dive trip then 2 more days back in SJO re-checking the plumbing.
https://www.padi.com/dive-shops/herradura/For TLN might find a 30ish Tica in SM's not as hot (3-5/6) willing to stay with you the night (maybe). I was offered it some years ago from this type of woman if I wanted.