A thing that is close is sometimes said to be a stone’s throw away.
Example: Mary Jo’s house is just a stone’s throw away.
Why are you throwing stones at Mary Jo’s house? Mary Jo is unpleasant to deal with on her best days and can be downright villainous when she’s in a bad mood.
Do you remember that time the paperboy missed her porch and it landed in her hydrangea bush? He still can’t talk about it without weeping uncontrollably.
And now you’re pelting her house with stones–what the hell are you thinking?
Can you imagine what would happen if you were to break one of Mary Jo’s bay windows? You might survive the aftermath, but I am fairly certain your testicles wouldn’t.
Besides, it seems wildly arbitrary to determine distance by how far you can hurl a stone.
Is it a small stone or a large stone you’re throwing?
I would think it also greatly depend on who is doing the throwing. I’m sure Roger Clemens can throw a stone a great deal farther than you can–you’re basically a tiny weed of a man. (Even more so since you broke Mary Jo’s bay window.)
You shouldn’t be throwing stones around all willy-nilly anyway. Have you ever accidently hit someone in the side of the face with a stone? They get mad.
Or try explaining to your neighbor that you were just trying to determine if his new truck was parked a stone’s throw away from your house after you’ve put a huge dent in it. He will be less than understanding. “You’re just lucky I’m not Mary Jo,” he’ll growl angrily.
Just look at a thing and estimate in your head how far away that thing is–you’re an adult, you can do that.
But don’t spend too much time looking at Mary Jo’s house: she gets suspicious.