Bill, I wouldn't plan on anchoring at either Avalon or the Isthmus at Catalina. If there was a decent anchorage, they've put mooring buoys there. I've anchored at Cat Harbour (south side of the Isthmus,) but that field has been filled with buoys. And at Avalon, you're outside the breakwater. For our small boats, the string line is a good choice and probably not as crowded. Anyway, good luck.
Boris