>Fire: should I conceal it at night, and how could I best do that? I wouldn't want to reveal my location to anyone.
Best not to use one. Or have a good shielding around it that reflects heat back to you and helps hide it. Don't do fires during the day. Look up a Dakota Fire Hole (if I remember the name right). Very useful.
>Do I stand a chance alone if I had tons of food hidden?
You need a reliable food source for when that runs out. Look up ways long term farming. Like the 3 sisters and similar. Also learning/knowing trapping can help for small meat gain. For hunting large game I have no idea.