glc, mark and southwest dave: thank you for the info and advice.
Ideally, I'd love to get to Denver within 2 driving days, but as I have a 2 year in the back-seat, I think it's in everybody's best interest if I give myself more time, just to be safe.
glc: If I don't wanna drive out of my way to SLC, where's a good halfway stopping point between denver and las vegas (that's on the highway) to stop for the night?