I'm finally going to stop lurking...this is my "thank you" to all the folks in this forum who (unknowingly!) helped me put together my month-long central/eastern European adventure. Hopefully I can help someone else out in return!
I am female and in my early 20s, traveling solo. I landed in Vienna then took the train to Budapest, Prague, Munich, Fussen, Florence, and Venice. I bought a Eurail pass, which I found to be fairly easy to use. The flexibility and peace of mind were nice. Train reservations were no issue, as it was mostly shoulder season.
I stayed exclusively in hostels through Hostelling International or Hostelworld. All felt safe and very clean.
Gear: I had an Osprey Meridian rolling backpack with clip-on daypack and a very small crossbody bag for my wallet and phone. The suitcase was a great size for my things and I had no problems lifting it into the overhead bins on the plane, train, etc (I'm 5'4"). I had a pair of Josef Seibel fashion sneakers for walking. Cute and comfortable!
I had the AT&T overseas plan, which was invaluable for google maps and last-minute googling.
Things I wish I brought: vaseline, NyQuil, leave-in conditioner for my hair (curly and unruly on the best of days)
Things I wish I hadn't brought: iPad, so many socks my bulky bluetooth headphones
Things I was glad I had: flip-flops for showers, scarf, fleece vest, Dryfit T-shirts, ibuprofin, portable battery, pajamas, eye shades
Cities
Vienna:
I found Vienna very easy. Public transport was a breeze. LOVED the coffee culture. I bought the ViennaCard off the app, which got me a reasonable discount on all of the major attractions. Make sure you get the audioguide in the museums and attractions! There is very little written explanation.
My favorite locations were the Schonbrunn Palace and gardens, the Mozart House, and the Kunsthistorisches Museum.
Budapest:
Possibly my favorite city, and good just for wandering (my favorite activity). The Great Synagogue and attached Jewish museum are interesting, and walking distance from the Basilica. Great food everywhere and, while touristy, didn't have that "museum" quality that some downtowns have. Definitely still an organic, growing place with a fascinating history. I recommend hiking up Gellert hill for a vigorous walk and glorious views.
Prague:
Just too crowded. I found it exhausting, even in April. Yes, beautiful and evocative but overwhelmed by tour groups. I did go to 8:30 Mass at St. Vitus Cathedral, and that was glorious. Charles Bridge is uncrowded at 7am and very beautiful. Everything was mobbed by 10am.
Munich:
Quiet, lots of students. The Hofbrauhaus is a lot of fun and the Residenz museum is beautiful and enormous. I spent a lot of time in the English garden sunbathing. Dachau concentration camp is awful but a must-see.
Fussen:
2 hours by train from Munich, and near Neuschwanstein Castle. I found the castle to be a bit disappointing, but rented a bike in Fussen downtown and spent a day on the bike-only paths around the mountains and lakes. One of my favorite days all trip.
Florence:
Also very crowded, but manageable, and my other favorite city. Make sure to get a reservation for the Uffizi and Accademia. I did both in the same day and found it long but doable. The RS audiotours around both museums were great. My best meals were in the downtown but off the main drag -- look for the smaller places in sidestreets. Did not have any issues with aggressive shopkeepers or beggars, as I had feared.
Venice:
Found Venice overwhelming, so I only spent one day there, mostly wandering around and enjoying the atmosphere. Found it very overpriced, though the city is truly unique and worth a visit. I also visited Verona and Trieste on my other two days in the Veneto. Both were very fun daytrips and much quieter with majority locals out and about. I had no issues with my nonexistent Italian.