I'd try a gro-clock first. But if that doesn't work or doesn't sit right, I am a big believer of removing ones self from the struggle whenever possible. IIWM I'd tell my LO she is free to come in, but she may not wake anyone. I would set her up a place to lie down on the floor (air mattress, sleeping bag) and tell her she is welcome, as long as she is silent.
But I say that not knowing the backstory. Is she looking to begin her day at 6am? Or is she just looking for comfort? Perhaps a trip to the potty and then back to bed? Is she able/wanting to go back to sleep and just wants to be close?