Americans can travel with Interrail if they reside in Europe for more than six months. This must be proven with official documents. Otherwise, a Eurail Pass must be purchased, which is today almost the same as the Interrail Pass. Buy Interrail ticket!
The Interrail Pass is off-limits to Americans: It can only be used by European citizens and permanent residents of Europe. But don't shed a single tear; the Eurail Pass was designed specifically for non-European citizens to explore this continent from Seville to Stockholm.
If you're seeking peace and quiet and want to guarantee a window seat — or a seat by yourself — 1st class remains a good bet. A high population of business travellers means the focus is on quiet concentration more than sociability. Plus, I've never had to stand while travelling 1st class.
Eurail passes do not cover local transport like trams or metros, only intercity trains. Rail Europe is another company that offers similar European train passes.
If you purchase multiple tickets in a single transaction, the price will be the same for each of the tickets. If not enough of the lowest-cost seats are available, you'll pay a higher cost for all of the seats. Buy the tickets one at a time to make sure you get all of the lowest-cost seats available.
Generally, if you're traveling on one route multiple times in a day, an all-day ticket may be cheaper than buying two separate tickets, depending on the distance. However, if you're traveling on multiple routes on the same day, two single tickets may be the better option.