Stormheim is the zone you want to start it. For some reason Legion treasures are not worth any experience like they are in WoD...except in Stormheim. I haven't been able to find out any reason for this, and it's possible it may get fixed/nerfed at a later date. But for the time being you REALLY want to jump from treasure to treasure to augment your quest experience.
Thanks for this guide. In the preparation section, you could add Goblin Gliders which are always super useful. I also recommend picking Northrend Engineering and Draenor Archeology as temporary professions. The first allows the use of the loot-a-rang toy which allows looting movs from a distance. The second one is required to picknsome treasures in Draenor.
Im pretty much Herb Alch for life because I like not having to rely on anyone else for my consumables. The addition of Sky Golem completely changed herbalism for me. All professions are represented with the 11 warfront quest and I can promise you if you know how to play the AH a little you can make a fortune off the items required for turn in. That also being said, profs were not a big focal point for me on my months of beta testing. I went herb alch on the first pre-made character just so I could have consumables for Raid and M+ testing.
I found that in most cases, I could pick the zones I liked and skip everything else. It was slower, but I still wasn't forced to do quest zones I hated (and, notably, I skipped the entire Cataclysm expansion's content -- sorry, Thrall.) I did do dungeons, both in group finder and by two-boxing (more on that in a moment as well), but only once for the quests, and mostly to clear what felt like an awfully long slog from 40 to level 80.
I made one for my guildies but its for the Horde leveling process. One tip that goes for both factions is that you dont need to do all 3 zones to hit 120. I did like 1 and than three quarters of another. But once your 120 you need friendly with all 3 of your factions new reps to unlock world quests so make sure you hit at least friendly with all 3 while your leveling.