Here is a ruling for you to chew on.
player A finds himself in a GUR garden bed, so he is entitled to a free drop.
Player A drops his ball and it rolls more than 2 club lengths and hits his buggy wheel.
discussion begins on ruling
is ball in play with a penalty for hitting his equipment.
does he re drop as rolled outside the drop area with no penalty
The ball can roll up to 2 club lengths from the margin of the drop zone but not beyond and then has to be re-dropped.
So no penalty and drop again, if it happens a second time then place where it first contacted the ground on the 2nd drop. If it fails to stay when placed then determine the nearest place it will stay and place. Ball back in play and play on !