Cats love to be up off the ground so is there another warm place up fairly high that she can go to? I usually put something on mine so he can not sit up there as he is way too big, you can see from my Avatar what size he is and when he jumps off the whole thing gets thrown sideways! It only took a couple of nasty accidents and I learned the hard way! I put up a couple of emply card board boxes which have stopped him. Other than that I would have to put him out and then he claws at the Cedar doors with his big claws and rips up the wood trying to get in. I have an old chair which he likes and I have his cushions on it and a snuggly cover, all hidden behind my painting stand, he seems to be happy when he thinks we can't see him!
Gal