Have never owned a yardstick since i left home. Def had one growing up. Will use the long handled duster thingie. Probs will just push it farther in.
That’s how you get cat toys out from under the refrigerator. I don’t think anybody actually measures anything with them.
If you have "blinds", some of them used to contain a small rigid sliver of wood in the bottom to keep the material straight across the bottom. These can be slipped out sideways, used for whatever purpose, and then put back. Careful, they're a might brittle.
Otherwise, one could employ an unemployed curtain rod. In desperate times, you could remove an employed curtain rod. Those curtains probably need washing anyway.
Depends how crazy the dog makes you.