In reply to Morgan Woods: From someone who hitched from Gap - all I can say is that it's a bloody long walk!
Even with cardboard sign with Sigoyer marked I walked much of D994 before getting picked up and driven the last couple of km to the turn off. Walked some more and after waiting for quite some time by the lake was finally picked up by a non climbing mother and son. They kindly drove me right up to the campsite.
Note this was quite a few years ago and I was a long haired hippy back then, so may have scared off prospective lifts?