Day 4 - Keystone, SD to ?

We crossed another time zone last night. Ally was not lovin' getting up this morning. Her momma agreed...where's the coffee?
Not sure how far we will go today. I'm feeling like our scheduled plan may be a little aggressive. We will be going to Mt. Rushmore this morning and then we're supposed to make it to Bozeman, MT tonight. I think we'll cut it a couple hours shorter and stop in Billings, MT so we have time to swim! We'll see how the day goes...