OK, so it needs a lot of work. I have a few ideas for changes that may be possible because we're replacing the roof, but if structurally risky or too costly, I'll live without them. Update: I'm living without several of them (see notes below and the May/June update).
Maybe an opening with a bar/counter between the dining area and kitchen (right)? Update: Possible, but it would be very small with a column on each side. Not worth it.
Living area facing front. Expand by opening the wall between the two doors (right)? Update: Could be opened only up to the door lintels, and supports would be needed.
The front bedroom could then double as an office and extension of the living room. Update: Office and guest room.
The wall seems thick enough for a counter opening, depending on structural support. Update: Thick enough, but see above.
With the stove where the sink is and the fridge to the left inside the door, hot or cold items could be passed through easily. Update: Not worth it.
Moving the back wall outward to expand the kitchen seems like a good idea, again if structure allows (see exterior view). Update: This will be done!
The kitchen will retain its basic configuration with plenty of cross-ventilation.
The bath will stay where it is but with modifications to the layout inside.
Back bedroom. It's not huge, about 3.5 meters square, but nicely laid out. Update: Hidden windows found behind the plaster in both bedrooms (left wall here).
It would help to extend this built-in closet to the left into the identical front bedroom closet. Update: Closets will stay as is but with space above for shelves.