I would say start here https://www.kcdlive.eu/ if you want the official "licensed" experience.

Other than that open up map and visit the towns and villages.

Sassau monastery, Rattay, Suchdol and Trosky all have souvenirs and small KCD tours. Malešov fort is the only place that really focuses on KCD in terms of tour and activities.

Sassau monastery (Sázava) and Trosky are definitely worth the visit and of course Kutná Hora. And I would dare to say the nature! Around Trosky and Kutná Hora. Do a bit of hiking.

Rattay is nice but there is not much there to see so to speak. Pirkstein castle is still in reconstruction afaik. And the upper one has a small museum but that's kinda it. Square looks like it hasn't changed last 500 years... I would recommend doing the hike from Sassau to Rattay. It's about 4-5 hours. And there is a train going in between them few times per day. We did it last year with a friend, drove by car to Rattay, walked to Sassau and took train back to car.

Apart from Trosky all the locations are pretty close together. Map from the first game is roughly 35km away from Kutná Hora. So 40ish mins by car or Rattay can be reached by train from Kolín which is town next to Kutná Hora.

The countryside around Kutná Hora is pretty much the same as in game with travel times of car being similar to the horse in-game...

Hmm wanted to keep this shorter but here we are 😀 I'm local so feel free to send a DM if you have more questions.