I know this thread is a few months old, but I just had to add in my 2 cents. The problem most people make when getting a ferret is they treat them like hamsters. A ferret is not a hamster. It's more like a cat or a dog. I had a ferret named Skipper, years ago. I never had the chance to take him traveling the way I am now, but I would and he'd of been great at it. As it was, he went everywhere with me around town like a small dog. We'd ride in the car, go for walks on leash, he had a cage, but was rarely ever in it as he was litter box trained (and he did NOT crap all over me, or anything else for that matter).
The draw back is that they are very prone to diseases. Skipper eventually died of cancer, but he had an awesome life with me and was VERY much loved. Here's a memorial video I made for him shortly after he passed that shows his life and some of the cool things we did together: