Wow, thank you all again for your replies. I am incorporating everything (don't have the cat litter yet though). In addition I am taking five gallons of water from our tap. When I get to Oregon I will start mixing it with the well water we use to switch her over. I also got her a new dog tag with my cell phone number.
The vet was supportive of this journey. She checked Sandy out and noted that she seemed very spunky. I got refills of her eye drops and vitamins and copies of her medical history including lab results.
I will take it slow. I have plenty of time and if I have to wait it out in bad weather then that's OK. I have $25k total of credit on my ccs, an ATM card and lots of cash.
Also, Mom's been paying almost $30 per month for Onstar and never used it, so I'll let them earn their money as much as I can.
Here is the route I am now thinking: Michigan to St. Louis, 70 to Denver, 25 to Cheyenne, 80 to Sacramento and I-5 to Portland. I think 84 is pretty dangerous this time of year, so it's probably worth the extra travel to take I-5 all the way up.
Thanks again to all of you. I have a laptop so hopefully I can post from the road.
-helen