We moved our daughter to her big girl bed at about 2 1/2. In the crib she was using a toddler pillow and a Halo walker sleepsack. Once she moved to the twin bed I gave her a full size pillow and a big comforter. We don't use the top sheet because she was getting tangled in it and it just wasn't worth the struggle. So she has a twin fitted sheet, regular adult pillow +pillowcase and a twin comforter. I wash the comforter more often than I would if she had a top sheet. HTH!
Anna, mommy to DD 11/06 and DS 3/10