Baskets on the shelves of the closet door will store a lot of the little items you mentioned. Since you have to leave room to open that door, I think you'll have to arrange the desk and chair with your back to the window wall or to the right or left corner. I see an outlet at the baseboard around the corner from the closet. How deep is that wall? You might manage some open shelves there it it isn't too tight. You might find a desk with room for a printer in a drawer and the tower could sit on the floor underneath.

decoenthusiaste both doors swing into the room (updated image). The main entrance door is the one on the right, the closet door is on the left. The only place that seems like I can put a desk is on the window wall, but I'm having a hard time figuring out the configuration and keeping it from being just a desktop and steel legs (too modern for the house), especially with the baseboard there. There is an outlet on every wall, but the one on the window wall is connected to the light switch (both plugs).

Well the entrance door is not an issue for desk placement since it is in a recess. You actually only have a 5'x 7'11" rectangle for the desk when the closet door/shelf is open. Here's is the best option to leave an open feeling to the space. Sorry my illustration is crude, but I think you can see how open it will feel like this.

Here's what I might try:

1. Obtain a L-shaped desk with a right-hand return. Position the return along the window wall to the right of the window. The desk extends away from the window wall towards the closet (when sitting at the desk you look to your right to look out the window). Allow some space between the return and the adjacent walls to eliminate the impression that the furniture is jammed into the corner of the room.
2. Check if the "cable box" can be mounted vertically. If so, attach a piece of painted wood to the window wall and hang the cable box on it. You don't want to set the cable box on the desk.
3. Unless the computer is enormous, obtain a bracket and hang the computer underneath the return. Position the computer so you will not bump with your knees it when sitting at the return or desk, or switching between them.
4. Attach cable guides to the underside of the desk and return to keep wires off the floor.
5. Optionally attach a keyboard tray underneath the return.
6. Obtain a table for the printer and position it under the window to avoid putting the printer on the desk. If the printer must go on the desk, put it in the corner near the window.
7. If there's space, put some shelves along the wall between the window and the closet. If not, hang some shelves or cabinets over the return to the right of the window.
8. Optionally change the closet door to a folding door so it doesn't project so much into the room. If there's space above the safe, attach some shelves or cabinets there.

-- amateur