Rich,
Hi! I am also in So Cal so I hear you on it being a high barrier to entry. So, here are some thoughts on your room.
Are you interested in short or long term rental (guests or someone who you live with on an ongoing basis)? Really think about it from a personal perspective - do you like meeting travelers? Or does the idea of strangers coming for a week sound less than ideal.
If you are open to both, do some research into your local part of LA to compare the numbers between short and long term rentals. Break out excel and see what works for you. For year leases, obviously there are all the standard ways like Zillow, Trulia, Craigslist and Rentometer.
For short term rentals see if you can find a vacation rental management company to call to get some info on occupancy rates and the ebbs and flows of the market. I did this for Pasadena and was very surprised by the data. Also, find some other folks doing short term rentals and talk to them. From some of the folks I have talked to, LA and its surrounds are great as you often get people in town who need rentals for say 3 to 6 months as they are working on particular projects or on assignment. These are great as the rates for furnished rentals are much higher. Obviously there is some more work with the higher turnover but depending on your situation it could be worth it. You can also always outsource that part as well.
Once you decide on the path, then you can look at best practices for that particular approach in terms of pricing, screening tenants, security, etc. Good luck!