Hi, Donna, you ask good questions. In my "old age" I find myself thinking about what kind of memories my grandchildren will have of me, what kinds of lessons my grandchildren will have learned from me when I die, etc. Such thoughts, I'm sure, were behind what happened a few years ago when I stumbled across some verses in Deuteronomy 4 about remembering what we've seen God do, and be sure to tell our children and grandchildren. (There are other Bible verses that encourage us to do that, too.) As a result, I developed a class on writing memoirs based on those verses. A number of people teach such classes, so perhaps that would be an idea for you. I suppose a weekend retreat would limit the time spent on such an endeavor but perhaps it would give people time to get started.
Another idea comes to mind: There's a blog and Facebook page called "My grandmother is ... praying for me," based on a book by the same name. The 3 ladies that run that would be great speakers for a conference like you described.
If I think of more ideas, I'll get back to you. Let me know how your plans fall into place!