The perennial 'which route' question!

I will be leaving this Saturday.

I will be towing a small boat, have a loaded down SUV, and will have my dog with me.

My gut is to do I-80, merging onto I-90 just after Chicago, as it seems to avoid most of the major cities. But anyone who has done both, or has current road information - would love to hear it and have my mind changed if that makes sense.

I'm planning five 8.5-9 hour days, trying to drive only in the daylight, not looking to break any land speed records, nor tour any sites.

Thoughts? Thanks all!