I don’t know a lot about this song. The Trip To Bountiful (When The Rain Comes) is an album track from The Adventures’ 1988 debut album The Sea Of Love and since I first heard it I’ve loved it, and it has one of the best modulations in any song I know, going from the dominant E major chord of a steady A major down into the dominant C# major, resolving into F# major for the rest of the song.
As far as the meaning of the song goes I’m not quite sure. There was a 1985 film of the same name, but as far as I can tell there isn’t necessarily a link between the two. Please let me know if you know any more about this song or film!