I just read Byron's lovely article "Food For Thought ... and Spirits", to credit the inspiration for this post.
Byron has a great advantage over me on this one. The bulk of my ancestors are buried almost 900 miles from me, in two Jewish cemeteries in Chicago, while she lives close to hers. And she has a different heritage of working with them. Jews DO visit their cemeteries, and DO work with each ancestor on the anniversary of her/his death, but decorating graves or eating/drinking at the cemetary is right out. It was a VAST break in Jewish tradition when we planted flowers along with burying my uncle Maury - but everyone at the cemetery service knew Maury and knew that he LIVED in his garden, so knew why we chose to break tradition in this way.
So where do I go now to honor my Ancestors?
Celts had several options. Tir Na Gog is 'in the West', and the Ancestors are often seen as part of the Sea/waters. Or they are said to be in the North. When I lived close to, but west of, the Chesapeake Bay, that West association didn't work well. I winged it. But now the Potomac is north of me. I'll do my major working on that river. Part of that will be a boat of food pushed out on the water, as part of my Samhain celebration.
But, as you know, I start the preparation work for Samhain well in advance. As part of that, I'll be sharing food and drink much of the month with my Ancestors. I find that efforts put in to renew the ties well before Samhain, when I will be out communing with them officially, pays off.
And, I'm assuming that all y'all already have ancestor altars you work with regularly, right?