May I suggest making a flyer to post at Senior Centers in your area? Some of us are not active on "social media" for various reasons. Some supermarkets have a bulletin board near the bathrooms that you can post on. Look on meetup.com for senior groups, join them and "market" your idea to folks you meet there.... Think of where your "target market" might go regularly: coffee, shopping, movies, laundermat, library, church/temple, salad bar, yoga, etc. Figure out a way to reach them. Plan a meeting, pick a space to meet, date/time, and publicize it; make sure to say What it's about, Who it's for, Where and When to meet, How the housing will work, and Why people might be interested...and an email and phone # to contact you with. (I suggest setting up a special email and Google Voice # just for this, forwarded to your regular email/phone if you want.) Good luck!
I've been away from L.A. for a long time. What area are you looking to do this in? Just curious.