Lost, I think you get one or two clubs lengths from the nearest point of relief but maybe you get an arc where you could go equally as far away (no nearer the green) on either side. So taking the unplayable you cost yourself a penalty stroke where you would have gotten a free drop off the path.
I'm sure Bill can tell us the right ruling...
_________________________
Golf is a game that can't be won, it can only be played - Bagger Vance