I'm pretty sure I'd have to build an RC sand ladder dispenser to do that.
What about four linear actuators with a tilting mechanism? Rotate them from horizontal to vertical then lower them until the mower wheels are off the ground, then tilt them back to move the entire mower backwards out of the holes. They'd have to be spaced out no further than the drive wheels though or I wouldn't be able to get into my backyard or close enough to mow areas around my house, fence, ramp, sheds, and other such things.