Seen these questions pop up a bunch, and there's some legit guides on wowhead
How world quests work: http://www.wowhead.com/guides/legion/world-quests
Ish about Legendaries: http://www.wowhead.com/guide=4149/a-gui ... egendaries
And to clear up a little confusion from yesterday: any dungeon quest reward is for any difficulty unless stated otherwise. I got a 840 ilvl trinket for clearing a normal mode.
Gearing through PvP isn't very viable--only really worth doing for honor talents and to prestige for the cosmetic rewards...aside from just being a general asshole of course. A great place for that is Helheim btw--it was a pretty big bottleneck when I was going through. You can still gear up through PvP, but you're relying on your luck for a good titanforge roll. Doing the other world quests or heroics is much more lucrative right now. We'll see how it is when the PvP season starts.