My odl man bought a Liberty safe about 2 years ago. Direct from the factory because the place he works had a special deal worked out with them. Basically got it for jsut over half price, and his company paid the rest. Part of their safety program he said.
Anyways, he said that when they delivered it, they had it on a trailer. They lifted it up somehow and put it on a "crawler". The crawler was remote controlled and on tracks I believe. It drove the safe off the trailer and into the garage. Then somehow it crawled up 3 stairs into the house and down a complete flight of stairs into his basement. He tried explaining to me about how it would adjust to different pitches of stairs, but I really didn't understand how it all worked. But it did. All they had to do was slide it off the "crawler" and into place once it was in the basement.
As mentioned before, I would call the company and see if they could move it for you, or if they knew of a better way than almost killing a few people trying to do what you think would work.