These are the original beams that were cut with an ax. If you look close they look like lincoln logs.
This house was built in 1811. The original house had a basement and two floors and a separate building for the kitchen, although to get to the basement you had to go outside. Later the house was added on that allowed the house to be connected to the kitchen. In the picture you can see the door to the kitchen.
This barn is called a bank barn because it is built into the bank of a hill. The lower part is where they kept the animals, and the top is for wagons and storage.
The green wagon on the right has a false bottom to transport slaves to a safe place. They put the board back in place, where we see the gap, and it looks they are hauling hay. It's a tight place, but I bet two or three could fit in there.