All of the above/some of the above/none of the above. Just pulling your thing E, there's some sections owned by the RCSC, some of county property, some the responsibility of the adjacent owners and some no one wants to claim. The Sun City Home Owners Association (SCHOA) has taken on the task of trying to paint and repair where needed. The acronym of the organization formed by SCHOA is SCRAP and perhaps aggie or her other half can fill us in more.
When I was looking at houses my realtor told me SC does the upkeep on the walls, not the homeowner. I see that's not always true. Don't believe promises about the Wall.