Would you consider building a closet that would hold the platform on which your mattress would be placed? The outer side of the platform could have drawers or doors to the storage units under the platform. This kind of enclosure would work better for a twin bed than for a double, but it would provide a place where the bed can be concealed during the day time. Then, if you could allow a path between the bed enclosure and sofa, you could have the sofa face the dining table, or you could place the dining table at a right angle to the end of the sofa.

Are there any photos that were meant to go along with your post?

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Paint the wall behind the bed the purple I have shared. Paint the headboard and door the gold from bedspread, white or grey. Pick up two standard pillows too to add to bed. Add a purple shag rug. Hunt the Internet for abstract glass decals to adhere to walls over bed. Your photo collage should go on another wall- over bureau perhaps - as it is currently hung to high. Putting it over the bed also makes it hard to see photos, which is the whole point. Check out IKEA for fun, inexpensive bedside tables ( not that color).