Do the encounter.
In case you already didn't know (some of you live in caves, I know) the Headless Horseman is a seasonal boss that spawns in SM:Graveyard. No pre-requisite quests, no foot work at all. Just show up with a group. He is a 5 man fight, a fun fight but not hard at all (did him with dps tank and 2nd holy paladin doing dps).
Why do you want to fly to Western Plaguelands and ride out to the Scarlet Monastery? Because the Headless Horseman drops [wowitem=34074]The Horseman's Signet Ring[/wowitem]. A very nice Epic Ring that is on par with Kara rings. Easiest healing epic you will ever get.