Welcome to Ohio!
For Geauga Lake: check around before going there on saturdays or sundays during july and august. For the most , GL is never crowded unless they have a corporate picnic, which can pack the place bigtime!
Best example: Cleveland Clinic Foundation Day. I have never seen the parking lot that crowded on both sides. I think Ted (coasterfanatic) went that weekend.
For CP, almost any sunday in October is great. ( i think the football games keep a ton of people out of parks.
Last year, our longest wait was MF and it was only about 5 mins.