I have my games in my basement (15 steps) and have always used a dolly, moving 10 games down and 5 games up. I’ve found the most success having the game on the dolly covered with a blanket and using ratchet straps to secure the game. One person on the side towards the upper floor and two people towards the basement. One step at a time and take your time. Good luck with Williams wide-bodies and JJP machines. Never tried the straps on the game but used them moving a freezer and had balance issues.