Consider 3 days in Prague and one in Krakow with a day-trip to Auschwitz, or 2 in Prague and 2 in Budapest.
One Week
Spend 3 nights in Prague with a day trip to Cesky Krumlov. Take an overnight train to Krakow. Spend 2 nights there before heading to Budapest for 2 days. Beach bums: dedicate 3 days to Hvar, 4 to Lake Bled.
Two Weeks
Start with 4 nights in Prague, then go to Warsaw for 3 nights, Krakow for 3, and Bratislava for 2. End in Budapest. Alternatively, book a two-week Black Sea cruise (popular ports include Nessebur, Varna, Contstanta, Odessa, Sevastopol, and Yalta).
