A stone's throw away means very close by indeed. Just a stone's throw away.
It is deliberately vague and is used most in advertising a property. The distance depends entirely on who is throwing, which is why estate agents like it.
1phrasea stone's throw awayVery close by indeed.
“The station is a stone's throw away and the shops are further.”
a stone's throw away is a phrase.
Practised in Idioms