If you're gonna be that close to the park you should give it a try. Though I'd be cautious about visiting on Saturdays while Halloweekends is going on. I've never been but I've heard it can get quite crowded. My friend went last year and said the lines for Dragster, Maverick and MF were over 2 hours.
Three hours can be a bit of a drive when you are limited to a day and a half. I would hate to be there and not visit but I guess if the crowds will be ridiculous then I would have to pass it up. My friend is not far from King's Island and I would hate to go somewhere that I can pretty much experience here.
Other than Mean Streak everything else is pretty smooth, you will probably love Millennium Force, Maverick, Raptor and Top Thrill. Corkscrew is the next roughest while Magnum only counts as "rough" because the penultimate hill gives you a dead leg and a gigantic bruise depending on where you sit. Gemini was tons of fun for me, not sure about anyone else though lol.
I've heard from tons of people that Halloweekends are the worst time to go, unless you really, really, really want to do the haunts. Operations there are phenomenal, but waits can still get pretty long. I really hate a day at a park when every single wait time is over 45 minutes.
I think it comes down to how much time you'd have. If you only have a day, I don't know if it would be worth it for what you'd be able to get done.
I did not care for Maverick. It was like I305 without the drop. The only rides there that I wanted to bring home with me were Millennium Force and Blue Streak. Dragster > Ka, but they're both kind of once-is-enough.
The amount you can get done in a day depends on what conditions are at the park. When I went last year it was 90 degrees, sunny and Dale Jr. Was visiting. OH, and they were announcing the new ride for the next season. During the course of that extremely packed day I got on every ride except for Top Thrill. I got on both sides of Gemini and rode magnum and millennium force four times and two times respectively. Top Thrill I got the next day before it started thunderstorming.