We'll be driving from the Ennis area down to Idaho Falls at the beginning of August. One alternative is going over to Dillon and coming down I-15; the other is 287 to 87 to 20. I know that road has gorgeous views, but it's close to Yellowstone and I'm guessing it will have heavy traffic at that time of year. We would rather forgo stupendous beauty in favor of Really Nice, if it means an open road. Can anyone give advice on the traffic on 287 and 87 and 20?