Coming to Costa Rica for 2 weeks in March (San José)

Hola y muy buenas desde Ginebra!
Estoy intentando organizar mi visita a vuestre lindo pais de 'Pura Vida' ! Pero tengo muy poco tiempo para hacerlo .. entonces, I would really love to get some tips and advice as Costa Rica seems amazing in terms of amount of things to do and see !

In a nutshell:
Am planning to visit San Jose: any nice/safe/simple places to stay anyone can advise?? Recommendations welcome! then restup on the Carribean coast for several days: any tips on nice b&bs and places to dive?
Then heading in land for some hiking, climbing in natural parks (if that can be done?)-- also potentially interested in horseback, white water rafting etc.

Perhaps the easiest might be to hook up with a good and reliable tour guide company tho typically i prefer to discover a country without being too much in touristy places.

Entonces, cualquier forma de consejos serian muy bien venidos ! Ya que no tengo mucho tiempo y hay tantas cosas que me interesan!! Un monton de gracias de ante mano.

Greetings from snowy Geneva!
Nancy