Dylan Martin on Facebook, Indiana mushrooms, has found something similar and is trying to id it. I told him about your find, but apparently he hasn't replied yet.

Being a member is encouraged but not necessary for the first walks. They're informal and educational. I think you're a member of you can post here.

I plan to go as well. I'll stay the night at one of the parks and do Turkey run the next day. Over 2hour drive for me near Macy IN. If the foray is canceled I may not, unless lots of rain a couple of days ahead.

It sounds like you're on the right identification track. I can't help any more however. Thanks for sharing this find, it gives me hope. I saw 5 nice giant puffballs a couple of days ago together. Could have weighed 13-15 pounds all totaled maybe a week or so earlier.