Question to the experts. (The Witcher 3: Wild Hunt)

In the game there are a lot of places where you could not get. For example, is it possible to enter in the prologue to the house of the hunter Myslova, how to get into the building of the water mill, across the river, in front of the White garden, unlocked the door of the most Western house on the hem of the fortress of Vranici, after the bridge over the moat to the left until it stops? Going through the game again, I would like to know the answers, but the search gave nothing.