I agree the roads would be quiet. She probably left her property around 2 am when the pacemaker and watch disconnected from each other. Bars will be at least mostly closed by that time and most people are asleep at home.
I was able to use the Pima County Parcel Search site and her last name to locate the home. I don't want to share more details than necessary to protect the family's privacy but it can be searched. It showed that she owns a 0.97 acre property. In her neighborhood, the properties are generally that size and it is somewhat hilly so there are visual obstructions. The landscape is native with saguaros, prickly pear, and other plants that can grow to 10-20+ ft (the saguaros grow quite tall). So there is plenty of visual obstruction if you wanted to pull off the road and dump something. It would be difficult to drive through the landscape though off road, there's too high a density of plants.
Explore a place in a more immersive way in Google Maps.
www.google.com
This is her road, but to be clear not immediately in front of the house. It feels weird to post her address online, even as news agencies have posted photos of the home. I just want to give an idea of what it looks like.
In the summer here it is stupid (dangerous) to go hiking during the heat of the day and search and rescue constantly has to go out and rescue dehydrated heat sick people. So my impression is that there is a sizeable search and rescue group in this area based on demand.
Edit: planets -> plants