Mark's and Toan's [Kevin's] place is in a quiet but reasonably central area of San Diego, between Mission Valley, San Diego University, and Montgomery Field airport, with plenty of street parking. I don't know about public transportation, because I haven't used it. I stayed in one of several rooms individually rented out. The room is basic, but clean, comfortable, and quiet. The room has no heater or air conditioning, so it was a bit on the chilly side in rainy February, but the house is close enough to the ocean for temperatures to remain temperate. The shared bathrooom is kept clean and has a large, accessible shower. A kitchen with dishes and both silverware and chopsticks is available, and there is limited shared space in a refrigerator. A washing machine and dryer is available. Wireless internet was adequately fast and reliable.
Toan was a friendly and helpful host, and the communication when checking in from San Diego Airport was excellent.
I can recommend Mark's and Kevin's place and would book again.