I totally get it. You can actually buy sticky paper from target or amazon that comes in black. You can even buy decorative patterns.
https://www.amazon.com/dp/B082CPSVPW/ref=cm_sw_r_cp_apa_fab_isHDFbQ6MSPHP
You cam cut it to the size of the level of window that prevents her from looking outside. Easy to apply, and use a hair dryer to peel it off.
At work we used vinyl to close things off with white on the inside to reflect light better and black on the outside to make it look neat. For the door flap we used two long thin wood rods with the vinyl. The top one slightly longer than the shelf to keep it in place and the bottom one the length of the shelves to weigh down the vinyl and keep it closed.
We used something like this and this.
Obvs this can be done in lots of ways but this was for business application and it ended up being cheap while looking presentable!