A riding mower is essentially a small tractor, so moving it means handling fuel and a battery, loading a heavy machine up a ramp, and strapping it down securely. The ramp loading is where most injuries and damage happen, so take it slow.
Pro tip: A drive-up loading, or a winch for the cautious, beats trying to push a heavy mower up a ramp by hand.
Watch out: Ramp loading a heavy mower is the most dangerous step, so use rated ramps, go slow, and keep everyone clear of the ramp path.