My buddy and I are actually doing a very similar trip this summer. We are starting in Chicago and going to Six Flags Great America, Michigan's Adventure, Cedar Point, Kennywood, Waldameer, Six Flags Darien Lake, and Canada's Wonderland. We are doing this the last week of July and into early August. This is the timeframe I usually plan road trips like this and it usually works out well if you can deal with the heat. We did a Dallas to Chicago coaster road trip that same time frame in 2023 and it worked out perfectly.
In terms of new coasters opening by then, the only one I am somewhat concerned about is AlpenFury. I think by late July it will be open but I'm remaining skeptical. Wrath of Rakashakalaka is already testing so that will be fine. I'm fairly confident Siren's Curse will open by then, and hopefully TT2 will make it longer than a few weeks. This will also be my first visits to MIA, Kennywood, Waldameer, SFDL, and CW.
If I could recommend any time frame to do a trip like this, it would be late July or up until the last week or two that parks are still open daily.