What options are available from train or air travel from Lisbon to Madrid?
There is only an overnight train between the two cities. It is pretty standard for an overnight train. Lots of options for flying and more than likely you can find a cheaper fare than the cost of the train (though you do save a hotel cost with the train).
When I was in that area 2 years ago, I flew Lisbon to Madrid on TAP Portugal airlines. I don't remember the price off the top of my head but it was fairly reasonable as I had booked it a couple of months in advance.
I have made travel arrangements thanks to your helpful advice.