You may want to try and plan a trip back to Cedar Point. They have added some fantastic rides to their lineup since Magnum. If you make plans in advance to attend Cedar Point at times when the crowds are light (week before Memorial Day, first few weeks in June, and week before Labor Day) you should have no problem riding all of the coasters in a day. However I think you need at least two days at Cedar Point to fully enjoy everything. Also, if you can budget the extra money for Fast Lane you can easily do all of the coasters (with many re-rides) and more flat rides with minimal waits all day.