It's a pretty big lake, we've got our share of 40+ foot boats but they tend to stay more toward the southern section where it's bigger thankfully since I live on the north part. Lake Sinclair is south east of Atlanta, Lanier is north, it's probably about 2 hours away or so, I don't think I've ever seen it short of maybe driving by it on my way to somewhere else.
JBB, actually Dawsonville does have it's very own nudist colony if you are so inclined
http://www.paradisevalleyresorts.com/default.htm
Hard to tell exactly from this map, but I've circled approx where I live:
http://www.sammythieme.com/1098Lake_Lanier_GAe.jpg