I'm sorry, I have no time to rewatch Amachan yet to find that scene. Are you sure it was after she got back to Kitasanriku after the earthquake? The song, Kikyuu, as I recall is usually played during very dramatic scenes (Aki's first hearbreak, when Suzuka Hiromi found out Haruko is her ghost singer).
I am also wondering about the cans. It wasn't clear what was written on them. Maybe they're just omiyage or souvenirs from places she came from to present as gifts to people in her destinations.
I'm glad you enjoyed Amachan. I'm planning to rewatch it soon, and maybe make aegisubs (.ass) version of the subtitles. I've been meaning to, for a long time. Maybe when I'm done with my current project, Gou Gou.