Cho,
As a professional realtor here in SD for 11 years now, it is great to hear someone asking such great questions before investing! My advice, each situation is different and the first step is to lock down your financing. Then from there we can see what kind of options we have. If we are looking at an attached SFR, FHA and VA financing will be more difficult to get in on. A detached SFR would more likely work.
I know the idea of roommates is never ideal, but it may be worth while. I had a multi unit with two properties in the front that I rented and I lived in a detached house in the back where I rented the rooms to foreign exchange grad students at SDSU. I rented out the two largest rooms to get the most income as well. This kept my monthly negative as low as possible. I liked having foreign exchange students as well. They were more respectful of my property and they were only there for 6 months so if I got tired of them, I wouldn't have to deal with them for long.
Let me know if there is anything else I can be of help with.
Karl