We didn't stay in Sandomierz, but this is the contact information in case you would care to investigate it for your stay here.
Directions: on the main town square
Fancy staying for a night in a 16th century house right in the old Market Square? The building which is now a hotel and a restaurant dates back to 1563. I never stayed there, mine was a half-day trip, so I can't say anything about the service. But I explored the building a little when we went there for lunch. Its interiors are really impressive! Check also my Restaurant tip about this place for more pictures.
Rynek 27, Sandomierz
2 Ks. J. Poniatowskiego St., Sandomierz
Rozana 21, Sandomierz