NRA4life;
What model Graffunder? That weight would be about right for a B16, which is 40" X 27" X 60". Do not attempt to remove the door, it's really not necessary, & as has been accuratly pointed out, dangerous.
The 1/2" plywood is correct for pile carpet, also the solid bar rollers. Turning can also be done on a plastic, visquine, sheet if you can manuver the unit on it without too much bunching up. One guy on each corner & all just push, hopefully, in the same direction at the same time.
Or, use the plywood & rent a pallet jack & cut an 8' 4X4 to whatever lengths you need to block & manuver the jack. Usually two the depth of the safe & two 8" shorties that allow a corner to be blocked without interfering with a jack shift from end to side or vice-versa. Use enough plywood so the jack does not come off it & sink into deep carpet. That will almost certainly cause more excitement than you want to have. If necessary, bridge any gaps in the ply with a couple of 2'X2' 1/8" steel plates.
I'm very familiar with Graffunder's & moved a B11 this morning. But then, I do it professionaly.
PM me if you wish to.
900F