Bed advice for two children room sharing

Hi all, I have 2 children, one who will be 4 in a week and one who will be 2 in August. We are unfortunately in the position that the children need to share a room for a while, but the room is the smallest room of the house (box) so will not fit two single beds. I am wondering if anyone has had children of this age in short bunk beds, so a floor bed and then bunk above? Did it work out ok? Did the younger one keep climbing up the top? Thanks