The lower elevation lakes will be open. I suggest you check with individual marinas and lodges to see what will be available in these areas. The weather will determine quite a bit during the opening weeks. June Lake Loop, Convict, Twin Lakes Bridgeport, open and fishable. The Mammoth Lakes Basin, Rock Creek Lake, South Lake will have limited, or NO vehicle access and heavy to partial ice on them. If you need cocktail ice or snow to fill your cooler and keep your beer cold, drive to 8500 feet and have your fill! I have a pic of Rock Creek Lake taken on 4/20 on the web at http://www.sierradrifters.com/fish.htm.