In Steves' book Europe through the back door he lists 10 cities that are good for day trips. Problem is, nine are in western Europe. Anybody out there have eastern cities to recommend that are easy destinations in interesting areas for day trips?
Dubrovnik and Rhodes.
Work it backwards. Find small places that interest you and then try and find a common denominator. I tend to do overnight "day trips" and look for train routes and cheap air routes
Gdansk, Poland Poprad, Slovakia Osijek Croatia Rzeszow, Poland Krakow, Poland Baia Mare, Romania Lviv, Ukraine
Kosice, Slokavia What are your interests? I guess it kind of depends on what you want to do, for example Sanok is good to explore SE Poland but mostly for hiking and wooden architecture.