The Castillo should be ok. It's not a favored hotel because it's a bit bare bones and the noise can be an issue in some rooms but there are many guys that like it a lot, and it's a personal choice. It's well located and close to everything, right around the corner from Sportsmens and a short block away from New Fantasy and 2 blocks from Scores/Zona 2 (please don't limit yourself to just these venues. I'll try to post a map later)
The Castillo is at Avenida 9 and Calle 9. I mention this because you should not rely on addresses when moving around in San Jose. The streets do not have street signs and addresses are typically not used (they have been talking for years to change this, and might actually be starting to do so). Your issue with this is that many, if not most of the taxi drivers will have absolutely no idea where the Castillo is and will be asking for landmarks, which is how they navigate. I would say that the hotel is "sobre Avenida 9 a Calle 9 en Barrio Amon, atras del edificio INS. El edificio amarillo a la derecha"
You can actually say it any of a number of different ways. I would suggest that you ask the hotel what directions they use with taxistas there. DO NOT leave home without those directions in hand, or at least the ones I gave you, which will get you there. The taxi drivers are incredibly useless in San Jose, and it's amazing the holes of city knowledge they either have or pretend to have when driving people around. If the driver asks you if this is your first time in San Jose when leaving the airport tell him no. You will find that everyone giving directions will use multiples of "cien metros" which usually means a block, from some well known landmark or business, and then the destinations building's colour. Needless to say, sometimes stuff can be tricky to find. Whenever you're going anywhere get good local directions, not TripAdvisor type directions.
Have fun! Fell free to PM me if you need info of any type.