Cracow and Wieliczka tour one day trip I do suggest you to see also Cracow's old town and Casimir - it is definitely worth seeing before visiting Auschwitz - Birkenau Museum. Knowing history of the Royal city and history of Jews in Krakow allows you to understand more from the lesson of Holocaust. When being in the southern Poland, you should also visit the oldest Salt Mine in Europe inscribed in UNESCO's 1st World List of Cultural and Natural Heritage, that is situated in WIELICZKA.
All of this may be seen within one day:
9.00 - 14.00 Sightseeing of Cracow as a city: Market Square, Royal route, Wawel Castel, University and of course the former Jewish district of Kazimierz with its synagogues, praying houses, Galicia Jewish Museum, Old Synagogue exchibition of Judaics.
14.00 - 15.15 lunch break Transfer to Wieliczka (10 km from Cracow)
16-18.00 visit to the Salt Mine in Wieliczka - you will have a chance to explore one of the biggest Polish tourist attractions (tickets: 50 PLN per person = approx. 16 USD)
18.00 - 18.30 - transfer to Cracow