Searching for a cottage up north (i.e. northern Michigan)

I’ve just cracked open a new vacation-planning effort – a summer trip possibly to northern Michigan. By this time, our summer plans are usually more solid – but with one kid going off to an as-yet-determined college with an as-yet-determined start date, I’ve had to hold off. Now I’m wondering if I’ll be too late to find a place – especially one in the third week of August, which for now (and this could change) appears to be our best bet for everyone to get away. I do have some good websites to start my search: VisitupNorth.com and Leelanau Vacation Rentals.