I made the opposite trip (mid-MI to western slopes) this summer. Make sure you check out charging stations via PlugShare. Last I saw, the Ogallala, NE charging station was a POS. My experience is that the stations in NE were somewhat more problematic than other states. On the return, I did have fewer issues, perhaps because the temps were 20+ degrees cooler than when I was headed to CO.
If you're looking for places to stay, I highly recommend the Revel Hotel in West Des Moines (Urbandale), IA. Great hotel with a free breakfast. Their corn cob smoked bacon is wonderful. Right next door is The Machine Shed, very good home style food, like a very upscale Cracker Barrel.