In La Fortuna try
Get a day pass, rent a locker to store your stuff for 6.00 big enough for 2 easy. Towel deposit is about 10.00 each, and you can swap your towels as often as you want. Get your money back when you return towels and leave
https://www.baldihotsprings.cr/http://www.donolivochocolatetour.com/ This was enjoyable and felt worth the 25.00
http://cavernasdelvenadocr.com/index.html This I highly recommend only 25.00 each and you can spend the day there. Take change of clothes and swim trunks to use the pool after your done. They do have a resturant on site but we did not try it.
In La Fortuna eat at
http://www.restaurantelaparada.com/ for local food at reasonable prices. Plenty of places to eat but a lot of them are pricey. We kept going back to this one.
As for mongering in La Fortuna there were plenty of girls if you look but be somewhat discreet, also a fair amount of tourist females that might be an option if you want them. Places do close up somewhat early but we found late night drinking spots every night.