Oliver,
Welcome to the board.
I'm sure that you'll have a great time at the beach, surfing and doing yoga, but I have to agree with ChiTownGino. 24 hours in SJO? ....And at the very END of your trip???
Here's a suggestion.
Since you're going to be in CR for 2 full weeks, why not try SJO on your 1st night, and
then go to the beach (if you're still walking)! This way, you'll get a 'taste' of the SJO scene, and you'll have the option of staying in SJO another day or two, or possibly coming back to SJO for a couple days at the end of your trip.
Just a suggestion, but I think if you wait until your last night to experience the gulch, you'll end up kicking your own a$$ for not staying there a little more during your 2 weeks in CR. And, by that time, it's too late. It'll be time to get on that big bird to fly home. Think about it.....
Have a great time, and welcome aboard.
Mucho Gusto
