DD wears a singlet, one of the sleeping bag suits from Target, her cotton sheets (because I keep forgetting to buy flanlette ones), a bunny rug (I just can't seem to stop using them!), and a cot quilt. As the weather cools off, I will add her sheepskin underneath and also add blankets on top. She has a lovely wool one.
Last year (we only intoruduced the quilt this year) she wore singlet, PJ's and sleeping bag OR just a sleepingbag suit, cotton sheets, bunny rug, and the wool blanket doubled over as well as the sheepskin underneath the sheets.

DD also has a matress protector on her bed which I think helps keep the cold away a bit - could be wrong but it is what I find when ours is on...

HTH

MG