[ViaxobbimeVar]

I read of hungry ghosts, samadhi, hells and a void like Nirvana and don't find any of this very practical.

You do not find them practical because you do not have a jigsaw to connect it to your daily life.
If you practice to be aware of your mind real time, you will see that all of these are practical.

For example, when you feel greedy for anything, your mind is hungry like a mind of 'hungry ghost'.
When you feel angry or hate, your mind will be fired like a mind of 'life in hell'.
When you concentrate to something very much, your mind has 'samadhi'.
When you put down any Dosa, Lobha, or Moha in any matter, you mind will feel light, soft and/or comfortable.
It is not Nirvara but it shows you that 'Nirvara' should exist and it is feasible to reach there.