Looking for a place near SA that I can take the family and camp and have a resonable chance to catch supper? Thanks

Probably Braunig Lake would be as good as any that I know.

Also, I see guys fishing from the bank at Potters Creek campground at Canyon Lake (it's where we go when we stay a few days, but we have a boat):

A reasonable chance?

I'd have to say Braunig or Calaveras, and I'd lean more toward Calaveras if supper depended on it, since I never did all that well at Braunig off the bank.

Take a castnet just in case, since it's great for catching bait and if you don't catch anything you can eat the bait.

Seriously though this time of year fishing between fronts can be tough anywhere, so taking along some fast food or fried chicken, might not be a bad idea.

As I recall, the only places where I camped and could always count on catching "dinner" were Amistad and Toledo Bend (BUT, we fished from our boat).