It sounds like you could use the help of a local real estate agent.
Send me your email to JamieTian@RodeoRE.com and I would be happy to send you a list of properties that fit your criteria.
I would look for a "single level" home for you, or a single level condo (they do exist).
. I would also put you in touch with my contractor who specializes in accommodations. He installs grab bars and hand rails and other conveniences that make life with a disability easier. You will most likely have to add these to any older home you find. The newer Condo developments will have some features, but rarely will you find the grab bars pre installed.
I became curious about the availability of homes with accessibility features after answering your question and performed a search for all the homes that have them which are west of the 405 Freeway from Pacific Palisades to the airport.
Surprisingly, only five listings came up. Four are south of the 10 Freeaway and all are under $1M. The fifth is just north of the freeway close to the Exposition light rail corridor that's under construction. I'll be glad to send you these listings if you'd like.
I was amazed that there aren't any listings in Santa Monica or Palisades right now that are designated as having these features.
There are accesibiity fields available when agents and brokers list properties for sale on the MLS. Any real estate agent/broker should be able to perform searches for you using professional programs that sift through the many properties on the market for only the ones with various accessibility improvements.
I don't know how much of this functionality is included in online search tools that are available to consumers though it seems like you've had difficulty getting this kind of information. I'd like to add that there are plenty of other good reasons for having an agent early on in your search for a new home... but that's another subject.
Best of Luck