As far as I know, he has attended two reunions. In the late 1990s a group of us gathered in Hartford, CT, where Richard was appearing in Edward Albee's "Tiny Alice" at the Hartford Stage. We celebrated his birthday with him and he shared his memories of working on "The Waltons" at a banquet. A number of cast members were there (Judy Norton, Jon Walmsley, Lisa Harrison, David Harper, Mary McDonough, Joe Conley, Eric Scott, Leslie Winston, Lynn Hamilton, I may be missing someone). Ray Castro produced a birthday greeting video that some of the other cast members appeared in.
A couple years ago he was at a Hollywood Autograph Show in CA. I did not attend that and do not remember who was in attendance, but there were a number of cast members there with him.
Normally he is working when these events take place and cannot attend.