It will take you about 10 minutes to "comb" the lake.
I agree with everyone else - morning is your best chance for good water. The water is pretty cold too but I have bare-backed it in the summer. I don't think it ever gets any warmer than low seventies but in June you are probably looking at low to mid sixties, burrr....
Just out of curiosity, are you taking your boat or do you know someone there that's got one? The North Shore Landing rents (at least they used to) time on their boats and offer lessons if you are interested. If you are taking your own boat make sure you have a good tow vehicle - the road get pretty steep in places.