It should be doable in a day or two. There are couple of things that are sort of timegated, the broken shore WQ’s (you have to complete certain amount of WQ’s and there are cooldowns on WQ’s).
Also, you need to beat a legion invasion and the usually the last part needs a group of 3 people to do, so getting a 2 other random players on a 6 years old content might take a while.
There was also a quest in Broke Shores where you had to kill demons for a low droprate item, that is the most frustrating part of the unlocking class mounts IMO