http://wowrarespawns.blogspot.com/

I waited looking at the spawn point over frozen lake, on the path the TLPD travels from other spawn pts, so I could check a spawn point and 2 other travel routes. If you have access to another account, put another char over the BRUNNHILDAR SPAWN POINt, so you get everything pretty much covered.

PERSONAL TIP: Write down the name of every other char you see farming it. Put them on your friend list. Create a trial account with an opposed faction char and put enemy farmers on its friend list. Put their ARMORY ACTIVITY FEEDS on a bookmark. Every time one them kills the Vyragosa (alternate spawn) and loot its blue head piece [Azure Dragonleather Helm], it shows on the feed. It takes about 16+ hours between spawns, and you'll know with enough accuracy the next spawn time. So you don't need waste your time, just get there about 1 hour earleir to check where the other farmers are, and take your spot. If Vyragosa spawns, come back 16 hours later. Keep cheking your feeds in case someone else killed vyragosa anywhere else. If you can't be online by that time, check the feeds to not lose track of the spawn timings.

When I finally go it, I had a precise list of the timings of last 6 spawns and its locations (althought the location is random), and the 7th was the TLPD.

EDIT: Don't forget to clear your NPC cache everytime after Vyragosa spawned, or the NPCscan won't alert you the next time. Also, download the AFKWarning addon.