Since you are only going to be in town for a few days a guided trip is your best bet, but since you don't want to go that route it might be pretty tough to catch enough for a fish fry especially since it's the dog days of summer with the 100* weather so it will be tough.
You can try Calaveras off the bank but there again no guarantees!
One thing you can do since you mentioned Canyon, is right at the corner of 306 and the entrance to Potters Creek park there is Fisherman's Corner. It's a pay pond and there you can catch them yourself or buy them outright.
Some people might think it's a sin to fish a pay pond, but it's cheaper than a guide and pretty much a sure thing!http://www.canyonlakefishing.com/