I don't think your snake's behavior sounds unusual, especially after reading your previous post. She's probably just settling in and still getting used to her new home. I have one snake, Chai, who is very healthy and robust, but very, very rarely is seen roaming his cage (even at night). Sometimes he will poke his head out when he's getting hungry. My other corns, Emily and Alex especially, are a bit less timid and are often stretched out across the side of their tubs, and will even follow your finger along the side. Chai will zip right back in his hide at the sight of a wiggling finger!
I think she will start getting more active as time passes. As long as she is responding normally when you pick her up, and eating, I think she's doing just fine.