This is not really a topic for historians to answer, since you would be hard pressed to find a historian who is both an expert on Polish rural culture AND the Witcher series.

But the shortest answer is that: the Witcher series borrow very little culturally from the rural life of medieval Poland, but instead takes the vast majority of its themes from 17th century rural Poland, and the culture of the Polish-Lithuanian Commonwealth. Entire themes, humour, characters and parts of legendarium are lifted wholesale from the Polish Sarmate culture and late 17th century folktales.

But if you are asking more about archaeological/technical perspective, then yes, the Witcher series show the everyday technological reality of a peasant in a medieval-ish world rather well for a fantasy series. The huts, the inns, the mills, the carts, the tools used and clothes worn are not far off from reality, only very anachronistic, with styles ranging from 800 ad to 1800 ad blended together. Some of the houses and huts are even modelled on real extant antique architecture. The only obvious nitpick is that the fields and herds shown in the game are nowhere near big enough to support villages that size, even if we account for trade.

Urban life in the Witcher, on the other hand is heavily modeled on Reneissance Europe, especially Low Countries, France and Germany, with only a smattering of 16th century Cracov.

If you are interested in the relationship between Sapkowski's (Witcher's author) books and specifically medieval/early Reneissance culture, Hussite Trilogy is a better example, as is Maladie.

If you are truly interested in realities of the Medieval Polish peasants I can look up sources, but the vast majority will be in Polish.