Those house boats have been there for as long as I can remember, they are usually passed down within the family. I believe that they are seasonal though, most of the park facilities are shut down from 10/31 - 5/1 for the winter. I'm not 100% positive that the houseboats are shut down but I don't know how you would get to them? On the ice would be an option as long as the ice was safe.
The entrance to the pond can be quite shallow, only a couple of feet most times. At one time many years ago we had an aluminum fishing boat, I took my boys and my father fishing in there many times. It is a tranquil place that only the smallest boats can get to, I have photos of the boys and my dad holding up bluegill with BIG smiles, framed and up on the wall of our cabin.
I believe the houseboats are owned by the families but are there by permit of the DCNR of PA. The pond is actually adjacent to the USCG facility as well. The bay outside the entrance to the pond is Misery Bay. It is where Commodore Oliver Hazard Perry built his ships to fight the British in the war of 1812. Our tall ship Niagara was his flagship.