Easiest way I found to do it with the repeatable quests is just do Annals of the Silver Hand (Stratholme one). Fly to Plaguewood Tower and get to Stratholme. On your first run kill everything up to where you pick up the book right before the last boss in the living quarter. Run back/Hearth to Light's Hope or whatever. Turn in and re-pickup but DON'T RESET THE INSTANCE. The book will reappear and you won't have to fight your way to it on the additional runs. Each full loop from and back to the quest giver took around 8 min just running and using the Plaguewood FP.