While most college interns will spend the summer slaving away in offices, Elena Studier talked her way into something more dramatic: traveling 10,000 miles in 38 days in 20 major cities in 15 states. The Ithaca, N.Y., native convinced her bosses at the National Association of Rail Passengers that sending her on the trip would help promote how easy it can be to travel the county by Amtrak, local transit and bicycle.