Notes for Drunk on a bus

Drunk on a bus (DOAB) guy has fun getting drunk and taking the bus. He thinks about fun stuff, does fun things, maybe talks to people.
But there must be a story, so...
When drunk he gets drawn into a story: by talking to somebody or doing something he wouldn't when sober. OK but what is the story? Some ideas:

• He comes across evidence of a crime, like the film The Conversation.
• He gets recruited by "Them". THEM are looking for a person who will do the things he does when he is drunk. (THEM could be a confidence trickster.)
• Somebody likes him when he's drunk and starts a relationship

Whatever the story is, DOAB guy is attracted to it and has to get drunk and get the bus to stay in it.