We're two adults going to Cedar Point in October 2019 just for the park, not the Halloween thing. Are the crowds terribly large in the fall? Should we get the fast passes? Any advice?
Cedar Point crowds can be very bad in October, but they tend to be based on weather more than anything else. As with any trip to this park, I highly recommend holding off purchasing FastLane until you're physically in the park and can see how crowded it really is and how long the lines are. FastLane does occasionally sell out, but it's far less likely in October where most guests are visiting for HalloWeekends and are more inclined to purchase FrightLane, which is FastLane for just the haunted attractions.
Also note that Cedar Point has two different levels of FastLane with the more expensive version needed to expedite waits for the most popular coasters (Steel Vengeance, Valravn, Maverick, Top Thrill Dragster, and Gatekeeper). It's also important to know that the park doesn't open until 11 AM during October weekends, and the HalloWeekend activities start at 6 PM, so if you're trying to avoid the "Halloween thing" altogether, you will only have 7 hours of time to visit the park before scare actors start infiltrating the park. Even with FastLane it would be next to impossible to ride every coaster in the park in that amount of time because of the shear size of Cedar Point and the time it takes to walk around the massive park.
I may be the Cedar Point "local" in here, but I couldn't have said it better myself. If I had any suggestions, I'd recommend hitting the coaster must-rides on Friday night as much as possible. Friday nights in October is still Friday-Night-Football Night, and crowds aren't as bad then as on the rest of the weekend. You might not need the Fast Lane Plus if you get in the big rides then (check what's running, since not everything is running Friday night). You can then spend Saturday early getting what you missed and reriding what you want.
If you don't think you need Fast Lane Plus for Saturday or Sunday, you can get the Fright Lane for Saturday if you want to save a lot of time in the Haunt lines. They can get extremely long without it. I haven't done the Haunts in about two years, so they have change somewhat. I can't recommend what to skip and what not to miss, other than don't miss the Eerie Estate mansion if you have a thing for an amazing collection of antiques that are actually dustier than my house!
But you did say you're not into the haunts, so if you are serious Ride Warriors and want to get the most for your time, get Fast Lane Plus if the crowds seem to warrant it.
Expect crowds. HalloWeekends are among the busiest weekends of the Cedar Point year, and this year with the new Gold Pass I'd expect it to be absolutely jammed. Get there early, and plan on it taking time to get parked and get out of the parking lot.
Have a great time!
Thank you both!!