I would do the boxes next to each other (or shelves for art supplies & books), add a cushion on the boxed (shelf area) with textured pillows. Then add a leg to support the desk on the end with two chairs.
Would love a barn door in the bedroom going into the bathroom. But different than this exact one. Sliding doors like these ones can really save space in rooms. These are some of the coolest sliding doors we've ever seen - they even added a coat hook!
This nursery's motif may be a little dated, but love this idea of a very flat, simple mural as a backdrop. Even if I copied this exact mural, I'd definitely lighten things up - after all, it's for a sweet little baby.