I think he's random, so he moves between the Inn's and such. Although you'll never actually catch him travelling.
Actually in my experience, he stays put in one inn. I use a 360, I'm not sure if it's different on PS3 and PC.
Anyway, the quest only ever shows up in your journal once you get close enough to Sam for him to offer you the drinking contest so that could be why it hasn't turned up. Anyway yeah, he appears once you hit level 14, maybe even at the first tavern/inn you visit after leveling. I'd just check the inns in every town/settlement you may've visited at that time, or just all of them to be thorough. He's shown up in Riften and Whiterun for me, but he showed up in Ivarstead on one of my friend's games, so I'd check every damn inn.