I’m assuming your stats will be competitive and costs have been discussed. I would try to get a mix of visits to compare. Large vs small school, urban vs rural, etc. Give yourself at least half a day at each campus. Better to see one less campus than rush.
CMU and Pitt’s campus border each other so that could be one day. Then Michigan and maybe Michigan State. Go to Northwestern and U Chicago (if nothing else to see the architecture and see what a top 5 school looks like). Spend the last day at UIC. That leaves off Purdue and Wisconsin but you don’t want to rush.