Bob's Cove is closest to Castroville if you want to launch on Medina Lake.
Fishing places on Medina Lake.
Canoers and kayakers on Medina River.
Below the dam are little family owned places where you can spend the day and fish, swim, etc. I do not remember any of the names, but it you just wind around the Old Medina Dam Road, Lower Lake Road and Rio Medina road, you will find them.
Its a gorgeous lake and it is FULL.