Well, just read by the volume order.. It'll be fine even if the stories in volume 2 aren't in chronological order with volume 1 (The vol 2 is actually side-stories that happened along the time in vol 1), they'll make you develop to the story well (some of them actually become crucial for the next volumes). And don't confuse it with the anime episode order, they are different (the anime episode order is actually chronological based events so some stories from vol 2 were inserted along the story). It'll be in chronological order again started by volume 3+ so don't worry.
And about the side stories outside the main volumes, I don't know about it since I haven't read it. And the material editions are just like what is written there. They are just extras outside the main story, so I think they should be read after you finished the main story.
And I also think it'll be fine even if you don't read them, since they are just extras. Hope that helps.
Sword Art Online (Novel) - http://www.baka-tsuki.org/project/?title=Sword_Art_Online It's not licensed (=being published in English by any publisher), so you won't be able to buy the series in physical copy. You have to read it online, which is just fan translations. For online reader, I suggest Batoto (http://www.batoto.net/).
That's because it supports the scanlators (people who put manga online for us to read) more than sites like Mangafox and Mangahere.
The Baka-Tsuki link doesn't seem to be valid anymore as of this date - but if those reading this would still like a link, there is this archive list of all the volumes, though they may be translated differently: http://www.vn-meido.com/k1/index.php?topic=1198.0.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.