The biggest problem with a ferret is they are ACTIVE at night.. meaning: In the truck, in the hotel room.. when you want to sleep they are awake. *if I'm not mistaken wouldn't a mouse/rat be also active at night?
Some friends of mine had a couple of ferrets.. and they were always doing 'naughty' things.. hiding things, biting, and they had these really long.. creepy like bodies.. (ok, they reminded me of furry snakes!)..
And, I just couldn't see the cuteness factor.. no offense to those that adore and love their little ferret pets.
However, a cat would be great.. or a little dog.. after all.. they can sit in the seat and give you little 'winks' of understanding or glare at you like you are stupid.. which ever way is appropriate for the situation.
And, I vote for rescue animals.. I like the mutts (cat and dogs)..