you need 42000 rep. That is 4200 ‘tick’ awarded at 200 resources per rep. In addition you get either 1 or 3 marks which, for the most part, award 100 rep for 3 of them. For most time efficient way do it on ab battleground time. And get the quests in refugee point. There are people who afk grind rep but it isn’t as much as av.
I am not sure if the serious pvp premades do ab during the ab event as I started pvp AB during a av event.