The only thing I saw missing was a good flashlight; if you break down, it will get dark. Others have spotted other missing items. There's an electrolyte thread running now which has some good info; I like V-8 juice. Start out with more water and if you use more than expected you'll be okay. Cheap insurance. I like the idea of water riding shotgun, convenient so you can drink as you go.

No idea what kind of cell coverage you'll have, but the PLB should provide back-up in case of actual emergency.

Check the SUV's coolant, oil, tire pressure et al each day and you should be fine.