As an instructor i would recomend you don't go near any flight simulator until you can fly the thing properly by looking out the window.
I have seen it may times, all you will be doing is getting yourself fixated with the dials.
And as you have so much time before starting why not get some of the theory out the way.
If you can turn up with airlaw and say HP or coms ready to be sat it will make your life a whole lot easier. If you can keep ahead with the exams its alot less stress. I would suggest leaving Nav and Met until you start the Navigation exercises they make alot more sense then.
As your numerical the trevor Thom books would proberly suit. If not the AFE Pratt books are more of a lighter read. Both have the same info in them just some people find one easier to read than the other. Personally as an engineer I don't have a problem with Thom but some find the syle very hard to study.
Good luck and enjoy
MJ