I did not have the chance to meet Josh but he was very responsive before and during my stay.
He does every thing to make you stay a good one : bottle of water, delicious cookies, emails with some recommandations (for example for dinner) ... and bikes available for guests: I really enjoyed riding around SF.
About room #5, it is quite small but large enough for a tourist : you usually don't expect to spend too much time in the apartment.
One thing you should know about the place: there are 4 other rooms for airbnb guests and 2 bathrooms to share. So the place might not be very clean depending on the other guests during your stay