This guy mountained bike with his dog...some sort of DIY rig. It may or may not be something for a dog with spine issues. I stopped him on the trail when i saw him to ask about it and take a picture. He said the dog would go crazy everything he got the pack out to go and the little guy couldn't wait.
I have a beagal/boston terrier mix and he is an awesome dog and loves hiking. Glad to hear you want Peanut with you and you care enough to make it work.