Not the princesses, but many of the other characters have gigantic paw-like hands, and I've found Sharpies work best. Or at least a big chunky writing implement.
I like the idea of signing the inner cover of a Golden Book (one book for each character or two, as you could have another sign the inside back cover).
Our Authorized Disney Vacation Planners are here to provide personalized, expert advice, answer every question, and uncover the best discounts.
Let Dreams Unlimited Travel take care of all the details, so you can sit back, relax, and enjoy a stress-free vacation.