From the large parking lot at the intersection of Gold Camp Road and High Drive, follow the (now closed to car traffic) old road west towards the Diamond Couloir, which you can see from the parking lot. It is easy and fast skinning along this totally flat roadbed. Once you hit the corner where the road switchbacks, take a right up off the road and onto a trail. When you see a sign for Jones Park, look uphill to the left for a small social trail to skin/bootpack up (depending on conditions). This steep trail takes you directly to the bottom of the Diamond Couloir if you follow it straight up the hill.
Overall, this approach is pretty quick. Climbing the couloir after that is what can be time consuming.