I tell you my experience. I'm leveling a priest that it's 60 now and since I have also done some instances (and I have full heirloom set with 20% experience gain bonuses) and been very ahead of the guide, I skipped some zones since they were grey quest for me, well it was a real mess. Missing quests because I didn't to the previous to enable the following. Going in a zone then realizing that I couldn't do that quest because I didn't do the starting quest chain, very unconmfortable. In short what I suggest you it's not to skip areas, or make really sure that you do all the quests required (at least) and check carefully the previous zone you'll going to skip to make sure that you won't have problems with struggling finding where to start the quest chain to sync with the guide section.
Taerar - Alliance Taerar - Horde Talnivarr - Alliance Talnivarr - Horde Tarren Mill - Alliance Tarren Mill - Horde Teldrassil - Alliance Teldrassil - Horde Temple noir - Alliance Temple noir - Horde Terenas - Alliance Terenas - Horde Terrordar - Alliance Terrordar - Horde The Maelstrom - Alliance The Maelstrom - Horde The Sha'tar - Alliance The Sha'tar - Horde The Venture Co. - Alliance The Venture Co. - Horde Theradras - Alliance Theradras - Horde Thrall - Alliance Thrall - Horde Throk'Feroth - Alliance Throk'Feroth - Horde Thunderhorn - Alliance Thunderhorn - Horde Tichondrius - Alliance Tichondrius - Horde Tirion - Alliance Tirion - Horde Todeswache - Alliance Todeswache - Horde Trollbane - Alliance Trollbane - Horde Turalyon - Alliance Turalyon - Horde Twilight's Hammer - Alli... Twilight's Hammer - Horde Twisting Nether - Alliance Twisting Nether - Horde Tyrande - Alliance Tyrande - Horde Terokkar - Alliance Terokkar - Horde Thermaplugg - Alliance Thermaplugg - Horde
Congratulations on reaching Level 120! There are a myriad of new things to do. The first thing you should do is head to your faction hub ship where you have been doing your mission table quests and footholds to pick up and complete the quests necessary to unlock World Quests. World Quests will provide you an opportunity to grind reputation levels, acquire gear, and gather Azerite. There are tons of new things to do that we will cover in our Level 120 Battle Guide found here: Level 120 Battle Guide