Here’s what we bought for Arthur:
It arrived yesterday and we spent most of the evening assembling it. I must say it was worth it though. Arthur just loved it, climbing up and down the ladder, hiding under the bed (there’s a small door at the side) and having a whale of a time. It’s big enough to hide a calf and all the cattle supplies he might need for it, but I’d better not give him any ideas and just hope his animal phase will soon be over.
I bought a mattress protector for it, but there was no need! He was dry all night! Not bad for a 2 year old huh?

That looks terrific. He will enjoy having that. I love the storage.
@Karen: yeah, he positively loves it .. and I have somewhere to hide now too