Nigel's point about the overnight trains is a good one. My wife and I went overnight from Frankfurt to Berlin. At midnight, we arrived at Hannover. The next train left at 2:45 AM. Once on the train to Berlin, my wife decided to read for an hour (??). We got 2 hours of sleep, and were useless the whole next day. I've done nighttrains where you could sleep, but it's another thing when you do not have 6 solid hours to get some rest.
I see that OP has revised his itinerary. 2 cities max, my friend. Remember, you are traveling to see something other than the mode of transport. They say that the journey is more important than the destination. All seasoned travelers know that this comment is totally wrong and idiotic. The destination is what you want. The journey just gets you there.
One other point - of all your destinations, Switzerland is by far the most expensive. If you are on a limited budget, consider Croatia, Austria, Germany, Hungary. If I were you, I would go to Vienna, Austria for 4 days and Budapest for 4 days. These are wonderful cities, with a great culture, lots of students (ruin pubs in Budapest are really cool), and are not as expensive as Switzerland. By far.