I am looking for some advice on what astronomical is available for my
needs. It needs to be free!

I'm looking for a basic package to show the predicted path of the
main celestial bodies (sun and moon and the biggest stars) throughout
any day of the year.

I also need to be able to read off azimuth and elevation for a given
day so that I can then work out which hours of that day I'll be able
to see the sun.

Also useful are times of civil and astronomical twilight.