The Taxidermist House, located east of Strawberry, is only accessible in Red Dead Redemption 2 by completing the mission "A Better World, A New Friend." as part of the "Hunters Sought" challenges. The owner of the house is Mrs. L. Hobbs.
While inaccessible in free roam, the house can be entered and explored through the use of an exploit. You walk around, take pictures, and leave.
Enter the Taxidermist House
Have a bow with dynamite arrows and full health. Climb on the lower roof at the west of the house and shoot the window.
Stand in front of the window, point the bow with dynamite arrow away from you to the edge of the roof and shoot. You will be kicked into the attic.
Point the bow with dynamite arrow to the roof and shoot. You will be kicked down to the ground floor.