if the person turns on the phone,even after a few days, would I still be able to track it?

Yes, as long as it can connect to the Internet, and the person hasn't wiped it.

And unfortunately you have to be looking at the "Find my iPhone" screen to see if it comes on. A bit like looking for meteors I'm afraid.

Not if you enable Lost Mode. It sends you an email when found, also showing a small map.

Stevejobsfan

Yes, you are correct - let me update this post