I won't be there but Plock is a very decent little city, well worth a visit.
Have you visited, Dobrzyń nad Wisłą, H ? - fantastic views of the Wisla from the hills, very historical little town, similar type of history to Kazimierz Dolny, once a thriving jewish community.
Mainly agroturystyka, the best hotels are Plock or Włocławek, which is about 20 KLM away from Dobrzyń nad Wisłą. A lot of Poles go there for water sports.
Here is another place I would recommend, zaborek.com.pl different part of Poland, there are some amazing places is the area, very rich in history.