As far as sanctioning, this is being planned as a rec league for the time being. If we got 200 people showing up on a regular basis, entertaining the idea of sanctioning would be a viable option for discussion if at that time it was available to do.
As for divisions, I would be willing to entertain any ideas you may have for this subject. That is the portion of the first post I made where I said I didn't have much experience. I'd love to put you on our organization team, with your permission of course. We could always use a person who has as much experience with league leadership as you, Scott.
I don't have that much league experience - I just know what works for my league. I'd be happy to answers you have. Not sure how involved I can be as I'm still thinking that we'll give TT another run this year.
Sounds like a great idea for a summer league, my primary suggestion will echo Scott's, if you decide to set yourself on a singles format with only one division you're going to have players who will be less inclined to return if they feel that the top 5 or 10 are going to be the same top pros or Advanced Am players that show up every week. I personally am not a huge fan of the handicap format though it's a viable route, I'd personally recommend starting with at least two different divisions.