The guide should advance to the point where you are in the zone's progression. There are a few steps that can-not autocomplete and they should (hopefully) have comments to the effect of -- you need to manually check this step off. -- For some reason you have to click these steps off 2-3 times to work. (the first time will move the tom-tom arrow, the 2nd time unchecks it and the 3rd click advances the guide).
Prior to update 7.3.5 it was far too easy to level up a new character. The experience needed to advance from one level to the next was too low, resulting in players out-leveling the story quests in each zone, moving on before getting the full experience. With low monster health and high player power (especially when players were outfitted in ridiculously powerful heirloom gear), creatures dropped like flies. Combined with easy experience gained by joining parties in the dungeon finder, the first 60 levels in the game flew by.
If you want to spend as little time on your alt as possible - just do Legion Invasions. You can use sites like (https://wow.gameinfo.io/invasions) to track when the next invasion will be. Log in, fly to the closest world quest, and once there - right-click on the quest's name in your quest log and "Find Group". Sign up for some group, or if there's none - just start your own immediately, and people will come to you. It is 10 times faster to do invasion quests in a group. Once that particular quest is complete - leave the group, and fly to the next one, where you should find another group. Don't expect the group from one world quest to follow you to the next. Then you simply log out until next invasion. You can do 1-2 invasions a day, and each invasion will give you about a level or 1.5 of experience, if you have full heirloom gear. Each invasion will take about 20 minutes.
The guide works great (of course expect a) BUT, after reaching 120 there should also be a guide to open and explore the remaining areas. Also, sometimes when multiple objectives are required, the guide forces you to follow in the order the guide prefers and if you don’t the objective is not rewarded. Gotta start catching up on the followers guides also. All in all, the $47 a year in-game guide is well worth it.
Edit 20 It’s been a week since this post and a lot of people are still reaching out to me with questions which is fine. I have had a few different people reach out to me to help make YouTube videos based off this guide and more info in BFA which I’m more than willing to do. Whoever gets the videos up first I will link them here for you guys to enjoy.