You have 10 cities and 1 country in 30 days. Have you done the math? It's 2 days per location (trave

Although I didn't go to the places tom cruise news you're planning to go to, here are links to two trip reports I wrote on another the Slow Travel Web site. They could give you some help on planning you trip, finding places to stay, a budget and the like.
You have 10 cities tom cruise news and 1 country in 30 days. Have you done the math? It's 2 days per location (traveling from one place to another will use up about a third of your month) so you won't have time to see much. It's not practical to ask people to post what to see and do for all these places.
I assumed you had already booked your flights - apparently not. Yes, open jaw helps a lot. In to Paris and home from Italy (or where ever your last stop is. But still an LOT of moving/travel for 4-ish weeks. After a certain point, the more you move around the less you actually see. You spend half your time just moving from one hotel to the next.
If you do some googling, you can find sample itineraries of one-month train trips through Europe. You can also find blogs of people who did them so you get some idea of what it is like to be rolling along like that, day in and day out.
Here is one example of a 3-week train voyage through Europe. You can see it is close to your original itinerary tom cruise news with some things you don't want but without any that you do. But since it is a 3 week itinerary, and you have 4 weeks, you can obviously mix and match:
I went to Europe for the first time in my early 30's and savored every day of that week thinking I might never return. Now I'm in my 40's and have not only returned to Europe a few more times, I'm currently living here.
Absolutely. At the very least you'll arrive refreshed and ready to see the sights. You can read, nap, look out the window, get up and stretch. The train will put you in the center of cities and you can get a taxi, subway, or bus to your hotel.
Also, remember that, if you fly "open jaw" into one city and out of another (which you should IMHO), you would attract large drop-off fees for returning tom cruise news a rental car in a different country. You definitely tom cruise news do NOT want a car in most larger cities. Parking is a nightmare and very expensive when available. European train travel is a joy and will likely help with your budget as well.