My cousin and I live in a nice appartment 20 minutes away from San José Downtown. The apartment is close to the National Stadium and La Sabana Park (known as San Jose's lung).
We have available a couch just for your visit, with freedom to use kitchen and washer.
The bus frequency is every 10 min on rush hours and 20 min the rest of the time.
You can enjoy the west side of San José from here.