I am going at the end of April. I wanted to get Ceasars for a 4 night comped stay Wednesday through Sunday and for the first time in years found myself denied a comped room in any tower at Caesars. They weren't showing sold out, just had a price. I dropped in and spoke to a host when I was there a couple of weeks ago and she had no idea why the system wouldn't let me in and booked a reservation for those four nights. Said she would try to get me into the new Octavious tower, but I would at leat get Augustus.
Anyway, I don't think thos nights are actually 'sold out'. I think they might be holding back some of the comped rooms though. A quick check on my account for the 1st weekend of March Madnes, for example, shows comped room availabliity in Forum Tower at Caesars, the regular rooms at paris, and the hollywood Hip at PHo, other options at those hotels come with a price of close to $200/night. That is not as good as I can usually get at these places, but they are not sold out
I think as the calendar approaches your travel dates, rooms should become available