
Originally Posted by
Midwest Michael
As others have stated, you really need to plan on a minimum of 4 days each way - so 8 total round trip. Doing that will already require you to drive nearly 650 miles every day, which is already going to be about 12 hours on the road each day, leaving very little extra time for anything but driving, quick stops for food/fuel/rest/etc, and is at the very top end of what you can safely do. If you wanted to actually see anything along the way, you'd need to plan for more time on top of that.
I will note, that for your return trip, you could look at taking I-40, and then cut up through St. Louis, Indianapolis, and Detroit just for some different views. The mileage is about the same as taking I-80 and I-70 through Chicago and Denver, so you'd still need a minimum of 4 full days, and if you wanted to make any extra stops (like the Grand Canyon, which is just an hour away from I-40) you'd need to plan for another day on the road, but at least you'd be looking at something different out the window.
While I'm sure the young driver fees are already very expensive, make sure they include every underage driver - as additional drivers also mean more extra fees, and if the driver isn't listed on the contract, they can't legally drive the car.