An easy AFK method is on the first level, Mansion.
When the guy lands, hold the left stick in the direction of the edge of the map. He will walk over, fall and respawn. Use a rubber band or something to lock the stick in place and let it repeat over and over until it unlocks. You may need to reposition the camera using the right stick to get the best setup.
Mind you, even if you just manually hold the stick in place it shouldn't take long to unlock, less than 10 minutes ought to do it.