Can't, Bob
First, moorings usually sell out within a day before a holiday weekend. Sometimes before. Second, your best bets are Emerald cove on the far west side and Cat Harbor on the back side, since they fill last. From where you are comming, I would tend to go around the back side to Cat Harbor.However, you can always anchor. You will want a minimum of 20' chain on the primary anchor and carry 300' of rode. Also carry a stern anchor with about 150' of rode and 6' of chain. There is good holding at Descanso near Avalon, but its a rolly anchorage. Also at White's and neighboring coves (good area for anchoring). Cat Harbor has lots of anchorage also. Anchoring just off Avalon is iffy because its really deep. The Isthmus Harbor has plenty of anchorage, but its also deep with kelp except off the camp grounds. At the Isthmus near the camp grounds and in close at Cat, you will likely need a bow and stern anchor.The key is get there before the weekend if you can for a mooring, but regardless, go with anchoring in mind and then you can not worry about it. Monitor channel 9 as you get close to find out what the situation is at the various coves. You have plenty of places in the bay to practice if needed. See you there!Rick D.