Put 2 more pillows to cushion the gap. (Our bed frame is slightly lower than the standard bed frame. If we got a bed frame with the standard height, it probably would have been leveled with her mattress.)
Normally if she woke up middle of the night, she would roll over, and snuggle beside me.
In the morning, all the bolsters and pillow will be removed, and we'll 'park' her cot against the wall.