It's pretty much an ending chapter, the point was getting Haruhi away from school and showing her desire to learn and grow as a person, not showing her new life. She picked a random city that made sense; she could've gone to New York or L.A. or any other huge city and the result would've been the same since this is not what the mangaka intends. Actually, I'm glad she didn't. There was no point to elaborate on the city they're staying in if the plot ends with their arrival. We don't see much of France and it's way more important to the plot. Why should we see Boston? This manga is targeted to Japanese girls, not fuck yeah! American nerds.