Her old standard sized pillow was a perfect fit.
The coolest thing about this pillow (besides the fact that it's a triceratops), is the detachable head! Yes, the head is attached with a wide strip a velcro, and is perfect for a little car or travel pillow.
Turns out she doesn't much want to play with these, even though the arms and legs move. She likes them better with the clothes off (argh, what a lot of work!!), because dinosaurs don't wear clothes. lol.
I have put the clothing away, and plan to make the dolls more decor than play sometime soon, once I find a good place in her room to put them.