I too am a veteran of 30+ college tours with my four kids. I remember the cmu tour being about average — not too memorable but not awful. Despite tour, DS ended up at cmu and is having a very good experience there.
Tours are hugely variable. Largely due to the personality of the guides but also institutional rules (“no dorm visit. Labs are locked today!”).
I’ve even visited colleges twice and had one outstanding tour and one terrible one (RPI, Yale). So you can’t really judge an institution by a bad tour.
By far our best, most illuminating college visits were when we had a contact there (professor, student, or friend of a friend) who could give us a true feel for the place.