I would NOT take him to dog parks. Dog parks are dangerous as is, and if he can't hear you calling or other dogs giving warning growls or barks, he could get seriously injured. I don't recommend dog parks to anyone, but especially not with a deaf dog.
Something I'd recommend- a lot of people get vests for their dogs that say 'I'm deaf, please ask to pet me' or something along those lines. If he can't hear people coming up behind him him, he could get easily startled by people touching him without warning.
I don't have experience training deaf dogs, but most of what I have seen people do is things with stomps (vibration- e.g. two stomps means sit), touching the dog (e.g. tap the head means sit). The easiest is probably hand cues, which many use anyway for hearing dogs. They develop pretty easily on their own when you lure a command.
For recall, I would get a quality e-collar and a trainer and properly condition the dog to it. Keeping it on a very low setting, you can teach him that the vibration means come. E collars are NOT shock collars and don't hurt the dog at all. That will be the only way to get his attention if he cannot hear you, and recall can be life saving. I personally believe that all dogs should be kept on leash until they have a reliable recall.