I'm in the preliminary stages of planning for a 35-day long backpacking trip to Europe. I originally was going to buy a one way flight from NY (any airport) to Madrid, Spain, and kind of start my journey there. From there, I planned to take the trains throughout western and a bit of eastern Europe, and end in Italy. From Italy (don't really know what city yet), I wanted to take a short flight to Greece to visit Athens. But upon further research, it seems that one way international tickets are crazy expensive, and its actually cheaper to get round trip tickets. But that would also mean me having to get back to the original starting location, in this case, Spain, which would mean extra flights and money to get back from where I end the trip (Italy/Greece). So I guess I have a couple questions:
Do you recommend flying into one city (Madrid) and flying out of another (Rome), basically buying (2) one-way tickets between Europe and NY?
If round-trip tickets is the better option, where is the most optimal place to fly in to? Is it better to fly in to somewhere in the middle of Europe (so I don't start on one end of Europe, and end up on the other end and have to buy a long flight back), rather than say, Spain? The places I want to visit right now is Spain (Barcelona & Madrid), France (Paris), Netherlands (Amsterdam, might cut this one out), Germany (Berlin), Czechia (Prague), Hungary (Budapest), Switzerland (not really sure where to stay, but I want to see Matterhorn, and Chamonix), Italy (Florence, Rome, Naples/Pompeii), and Greece (Athens) - I have it planned out roughly in that order right now, based on one-way ticket flights in to Spain and out of Italy.
Based on where I'm flying in/out of, what is the best route to take to visit all the countries named above? Also, more specifically, what is the best option to visiting Greece? I originally had planned to take a round-trip flight from Naples or Rome.
I know I have a lot of countries on there. Being a guy that wants more of the sightseeing nature-y stuff, and less of the night-life/going out stuff, which countries/places should I cut out (if necessary)? It's my first time in Europe so I still want to do the big things (Eiffel Tower, Coliseum, etc), but I'm much more interested in visiting places such as the Verdon Gorge, Chamonix, Matterhorn, Blue Grotto, Dolomites, and any other must-see places (please offer more suggestions!). Are some of the locations not worth going to in my limited amount of time?