Magnetic curtain rods and kitchen window tiers. Or make your own curtains from an opened pillow case using the hem as the casing. If you don't sew or your machine isn't handy you can use fusable tape to hem them.
Wal Mart carries this type of rod for under fifteen dollars.

You can get curtains on rods that fasten to the top and bottom of the window frame. Or you may be able to fit tension rods between the sides of the window frame and not drill into the door. Other options involve drilling into the door. You can get miniblinds that you can fasten on top and anchor on bottom. You could do shutters (expensive). You can get a window shade.

Or possibly some type of film that will let in light but obscure direct views. I've seen it at Bed Bath & Beyond, but I think there are other versions available at Home Depot and online.

Since you say living with these windowed doors is only short term temporary, go with the cheapest solution: RediShades. No hardware or complicated installation.

I got mine on sale at HD for $1.79 each. They don't leave any sticky glue behind when you decide to remove them. You can get them in paper (cheapest) or plastic, light filtering or room darkening, ect.

Here is a link that might be useful: RediShades

If you want something sturdier, functional, and not too expensive, check into magnetic roller shades. We had one on our back french door at our old house and it blended in well and worked great for privacy at night.

Not sure if this is the same brand we had, but it looks similar at least.

Here is a link that might be useful: Magnetic Roller Shade