Addressing her possibly going north to Denver. Nope. I highly doubt that.
There is major major major major road construction going on from the Springs (El Paso) area (just north of the AF Academy - 15min) up to Castle Rock (widening I25), called the GAP project. Most in CO should know about this, as 25 is a major highway going from Mexico to Canada. The area is a major mess and slow as hell. You will sit in traffic - no matter time of day.
There are backroads to get around that - but then that would take even longer. There are no mountain/plains roads that go directly into Denver. No frontage roads that are continuous alongside 25.
Like I said before - IF she wanted to get rid of his body
- going North towards Denver is not a possibility..............IMO of course.
South, East...maybe West into the mountains.