Training for 1st 2-mile Ocean Swim

Hi. New to the board...I have a few questions: I am training for a two-mile ocean swim in Southern California at the beginning of August. I have been in the water for about 6 weeks, swimming two days a week, around 2,000-2,500 yds. My first question: How many yards should I be getting in at each practice? And will stepping it up to three days a week be adequate for the rest of my training? Also, how much open water training do I need to do before the race? Will 3-4 times in the ocean be adequate? (I used to be a competitive swimmer and an ocean lifeguard...but I haven't been swimming for the last several years.) I am not doing this to compete, but to finish solidly. Any and all advice is much appreciated! Thanks so much. Hannah