>There are unspoken, untaught rules of life all around us

Yes, and there is no breaking truth, regardless of what you believe. 

> I have not heard of a friendly spirit that actually walks up to people and tells them what it is like to be dead. 

It is a funny thing, isn't it? 

>One thing we all know right now we are all alive, and at some point we will not be alive.

This is the thing. Work with what we know to be at least likely.