Cedar Point has amazing compacity so if you go on a weekday don't expect to wait long. Avoid the final weeks of summer as people are trying to milk whats left of it b4 they go back to school...millie was 2 1/2 hours.
Halloweekends is pointless on saturdays as haunt lines can get over 2 hours long and the place is packed. Sundays and fridays are better though, if you can stand to miss the outdoor haunts. Typically try to go in the middle of the week or sunday, and even saturdays aren't bad-millie 90 minutes dragster-1 hour, 20 minutes maggie, 30 gemini. The B&M coasters have the longest lines as Raptor is at the forefront of the park and mantis is down to two car opperations. Blue streak and Mean Streak are walkons closer to park closing. iron dragon useually is only 15 minutes. DT can have long lines (45 minutes) essecially on hot days as there is ac like none other in the line. Always try to arrive early and start from back to front (all the lines in frotier town are walkons till about 1130)
All in all, cp is great on lines for a park of its size and besides ttd, mf, matis, rpt, and dt, you'll probably be looking at 20-30 minutes tops on all the other coasters. hope my cp stream of conciousness wans't to hard to follow!