Starting off at some mid level? Come into the guide from any level, scroll through, find and click the level you want to start with, and the guide will take it from there. Zygor suggests starting the guide a level or two before your level. This is to allow you to work you way into the local quest chains. Just skip the chains for quests you didn’t pick up along the way, or the quests that you already did.
/way commands like /way Shadowmoon Valley:Draenor 50.0 31.2 Ashlei don't work correctly. According to the way TomTom works, this waypoint should be created in Draenor's Shadowmoon Valley. Instead, it will be created in Outland's Shadowmoon Valley. So it seems there is currently no way to distinguish between zones that occur more than once with the same name, such as Shadowmoon Valley or Nagrand.
Earning reputation in Kul Tiras and Zandalar can be done by almost any activity. You will passively unlock friendly reputation with each of your faction areas as you complete quests. At maximum level, World Quests will provide many opportunities to gain reputation in small amounts for each World Quest or one large amount per daily emissary. Warfronts will provide an opportunity to progress the 7th Legion and The Honorbound by means of Warfront contribution quests. Mission table rewards can grant tokens that boost your reputation level by a small amount. Despite this bonus being granted in small amounts, it can very quickly add up to a massive bonus to your most important factions, such as Champions of Azeroth. Even pet battles can grant reputation!