My rig is similar to kacnps'; 23' pulled with a Toyota V8. I just made the trip through Cincinnati last week, north and south, with no trouble on the cut in the hill on I-75. Other than rush hour traffic at 4 PM on Tuesday I didn't have any issues. Take your time, stay in the middle lane so others can get around you. Taking the bypass will add 20 miles/minutes to the trip (at best). If there's construction it will be even longer. There's a chance of accidents on any road you take.
Anytime I go through Cincinnati (I used to live there too, 8 years
) I go I-75 straight through and avoid the morning and evening rush hours. Personally, I fear I-75 in northern KY more than in Cincinnati. I traveled that road a lot over the last 25 years and I always felt better south of I-71 or north of the bridge. In between there's just a lot of discourteous drivers.