When I moved my dad's, 880lb, safe after he passed I used his dolly. This one.
I loaded it onto the dolly by myself. Moved it to the moving truck with a lift, onto the lift and up by myself. I would have been able to do the entire thing by myself except the lift and truck bed di not match up just right and I couldn't wrastle that thing over the lip ( about 1" difference) without too much risk of losing the upper hand and having it topple off the lift into the driveway. The same issue once I got it to my house.
My own safe, about 1250 lbs, was moved by two guys and a short pallet jack easily. One guy probably could've done it, but two made it look easy. They used a low trailer to transport, not a truck with a lift.
I don't think I would move my 1250 lb safe by myself now even with a pallet jack and I'd be afraid of damaging to 1000 lb dolly I have. Two friends and a 1500 lb pallet jack would be good. The bigger issue I see isn't moving it around as much as the vehicle that will get it from one place to another. How do you get it into and out of the vehicle? That seems to be the bigger issue to me. Two or three guys are not lifting a 1000 lb safe in and out of a truck safely without a lift on the back of the truck. IMHO