Did you check railsaver to see what it recommends in terms of a pass, or look at what flights will cost you? And if you were considering a four country pass, why not spend the extra $30-$35 to make it a five country pass? A pass might work out cheaper since flying Florence-Munich and Munich to Paris for comparable dates in 2010 looks like it will cost $130 & $150 respectively (cheapest I found, booking roundtrips with Lufthansa since one-ways are obscenely expensive for these routes).

Try www.whichbudget.com to see which low fare airlines fly which routes and check our “cheap flights” forum for more help and tips.

While overnight trains are not, IMO “a great experience” a flight has the potential for turning into a nightmare. Any flight takes about 5 hours when you add getting to/from airports, check-in time, security time to flight time, so the train often ends up being faster than flying. The 6 hour train trip from Munich to Paris could easily work better than a flight. A flight in the middle of the day will kill the entire day for sightseeing. An early morning train will get to you Paris before 13:00 or you could spend the day in Munich and catch them 16:23, getting to Paris at 22:37 — works if your hostel is pre-booked and the desk is open late. With a 16 day trip, I’d try to limit to a total of 2 overnight trains or intra-
Europe flights.