The mansion is only accessible In Red Dead Redemption 2 during cutscenes and the mission "Revenge is a Dish Best Eaten". After these, the doors are locked.
While inaccessible in free roam, the mansion can be entered and explored through the use of an exploit. You walk around, take pictures, and leave.
Enter Angelo Bronte's Mansion
Option 1: Place your bounty wagon or a stage coach under the main entrance, climb the wagon and jump on the balcony. Shoot the window to the right of the balcony door and crouch inside the house.
Option 2: Place your bounty wagon or a stage coach under the balcony at the back of the mansion, climb the wagon and jump on the balcony. Enter the house through the balcony door.
