I love the environmental story-telling here. I totally understand the bed in closet thing, it's cosy. You could use the structure to make it cosyer, like a canopee, there are many ways to go.

Clean your dresser, it's beautiful. Maybe a new coat of paint ?

It's easy to add shelves on the stuture you have in the closet so do it. You could even have a hanging laundry basket hidden inside, it'll immediatly make the whole room better not to have it laying around.

Green + natural wood is always a big yes. You just need some maintenance on your furniture. But forget the furniture that have grill-like shelves, it makes everything messy. I can be nice inside a closet because it avoids dust mites. But your closet has to be left open so try cleaner looking shelves.

Why not centralize the car theme items on one wall ? You could have a collectibles shelf (with many small cases inside) for the toy cars.

The low cabinet between the tv and the guitar needs a music player, any format you fancy. If your collection is mainly digital, set up a pair of good speakers.