Greetings!

I am planning a trip to Europe with my girlfriend in May/June of 2013. I am hoping for some feedback on our possible itinerary as we continue to plan.

Time Frame: May 19 - June 10 (19-21 days)
Departing from: Detroit, MI
Countries interested In: Spain, Italy, France, Germany Switzerland
Goal: See a mix of European cities and European countryside/outdoors

We plan to pack light and keep our trip predominantly a backpacking one. We plan to stay in hostels, trains and bed & breakfasts. We would like to stay in a nicer hotel 1 or 2 days in the big cities.

Here are the places we are interested in:
-Barcelona
-Paris
-Southern French coastline
-Italian coastline
-Rome
-Switzerland
-Rhine River in Germany

Proposed route of travel:

-fly into Barcelona (3 days)
-travel by train along Southern French coast (? Nice) - explore region (3 days)
-travel to Italian Riveria ( Cinque Terre) to explore and hike (2-3 days)
-travel to Rome (3 days)
-travel to Switzerland ( scenic train route and hike countryside) (3days)
-travel to Germany (travel down Rhine river, see some castles) (2-3 days)
-travel to Paris (3 days)
-Fly out of Paris

Here are my questions:

(1) Does this itinerary seem too ambitious? If it is, we wouldn't mind dropping Paris for this trip. Or, if people think that Paris would be a better experience than some of our other places we don't mind adjusting our plan.

(2) I am not sure how we can take one of the scenic train routes in Switzerland (Bernina or Glacier Expresses) and get to do hiking also (Interlaken?). Would it be wise to give up 1? Is there a good path where we would be able to do both?

(3) After Switzerland, we want to swing up and travel down the Rhine and see some castles. Where would be some good places to start or stay? I've read people liked places like St Goar, Bacharach, Boppard to stay. Would it be more an inconvenience doing our river trip since we are coming South from Switzerland? Should we start our itinerary in Barcelona --> high speed train to Paris --> then swing down North to South down the Rhine?


Any feedback is greatly appreciated. Thank you again!