We went to Poland last August. We actually travelled in a motorhome, but had no diffficulties when we arrived at our chosen site. We stayed at a site on the edge of Wroclaw.Olimpijski. it is by a sports stadium. Old facilities but clean. Trams from entrance to town centre. An excellent place to visit and we wish with hindsight we had stayed more than one night. We then spent four nights at Clepardia, Krakow. This is an excellent site, very clean, constantly cleaning toilet facilities. free wifi, washing machines. Very friendly staff who spoke English. Near to supermarket and bus stops to town centre. Security at both sites.
Roads are interesting to say the least once off the E40 and onto local roads can become cobbles and have lots of pot holes, so you need to drive carefully. definately worth the visit. We also went to Oswiecim, but not sure where the caravan site is. All sites listed in Caravan Europe. Enjoy.