I remember time when I was at teenage and I used to spend real money for wow gold from some suspicious "hacker" site from China or Korean what ever(note: I didnt spend much). And now I have realized how foolishly I did even I didnt about real money problems in there. Now that I have grown up I have also realized that I was one of those that caused playing problems for those young boys, that they had to play like 24/7 to farm gold for us lazy people.
I defintely think at 118 you should go and do all four of these parts. These are required to unlock World Quests and probably take about 60-90 minutes to get through. If you do these whilst levelling (especially all in one go at 118) then when you hit max level you're ready to go on WQs. You can go finish the zones quests at your leisure over the next weeks/months or never even finish them if you don't care about questing.