My back hurts just reading this post...
The hard part is that really only 2 people can get a hand on the dolly as it goes down the bulk head. And for the first 2-3 steps it is hard to get a good grip because the center of mass is waste high and the handles of the dolly are shoulder high. Not very good mechanics.
moving fees are a temporary pain, but back pain is forever... believe me...
One idea: if you really want to do it yourself and it is going down a bulk head you could:
1) Rent a vertical lift, like a
Genie lift, assuming you can get one rated for the mass of the safe that weighs considerably less than the safe (they make them, but don't know if you can rent one). Put it in the basement.
2) temporarily remove the wooden steps from the bulkhead (assuming your's are built like mine). You now have a ~8-10' drop into the basement.
3) Raise the lift platform up. Move the safe onto it. Lower it gently to the basement.
4) reinstall stairs and return the lift.
or... just hire they guys to do it!