If you want to be a total creep and spy on things from miles away, just get a camera like the Nikon P900. The zoom is so ridiculous it's scary. Check out the video by Fratila Angelo below that shows just how close you can get. It shows an excavator at work and when it zooms out, you realise you're seeing that from someone's backyard.
But, really, you don't actually need that crazy zoom.