Just noticed you are coming from Pomona, me personally I wouldn't go there opening weekend and I live 15 min away not an hour lol. I'd let a few stockings go by and see how the reports are, I've heard great and terrible things fishing opener weekend there. Once they stock it a few times the fishing should be good or atleast less of a chance of a total skunk which I have never had there that I can think of.
Also if there is rain out here don't bother coming out as the lake gets totally murky from silt and bird crap making fishing almost impossible unless your using powerbait.
If launching a tube you want to go almost to the very far right of the lake when facing the lake and there is a small paved ramp with carpet in the water at the end, kind of hard to spot but that is where tubers launch from. If you see any idiots set up fishing on the ramp like they are not supposed to feel free to kick their stuff in the water and make a ton of noise getting in or just snag their lines on your way out =). And watch out for cast-a-bubbles and 2 oz pyrimid sinkers coming at you from shore.