What a good idea!
We take the ashes of our people to our family owned summer home and scatter them there. I asked one of the younger generation who was there, thinking she would remember since she had scattered most of them through the years. She got a few people right, but not all of them and I was horrified that no one would remember since we have no stones or markers.
I started a book, using a journal with a lovely cover and an attached pen. I wrote down date of birth and death, along with date of scattering of the ashes and who was there. I left a few pages after each person's information for people to write their memories of the person. It's working out just fine and as people go there, they discover the book, enclose pictures and leave their memories. I'm happy because it hurt me to think that my beloved relations might be forgotten. They are the reason we still have the old place and they deserve to be remembered. I know that someday, I will be in that book too.