You can offer photography services to any business in the travel/tourism industry at your destination of choice. Opportunities are plentiful, whether you're selling your services or offering a trade. Going skiing in Colorado? Get in touch with local lodges about trading photography for a free stay. Vacationing in Vienna? Talk to the local tourism board about shooting a few photos for a fee. I recently made a deal like this in Cape Town shooting a month-long campaign with their tourism board, which resulted in a promotional blog post and lead to even more work. Remember that a strong portfolio goes a long way, and as it grows, so will your opportunities.
Another place to capture expressions are the subways; either on the platforms or in the cars themselves. My favorite images are the one of a young woman avidly watching a movie on her smartphone, while wearing a single hair roller to tame her fringe....and of the young girl who appears to be viewing a smart phone screen on an ad on a subway platform while her mother is busy texting on her real phone.