You get a special item that makes food that replenishes 2% health over time. Pretty bleh. But with the new patch coming soon and Achievements arriving with prizes like pets, mounts, and titles for us to salivate over, it's worth doing what we can now to prevent waiting another year to get that sweet-sweet Achievement love out of the way.
Levels 30+ have best success rate, but if a lower level is willing to corpse-hop a bit, you'll be on roads until the last little section.
Go to Ironforge, talk to the guy right outside and get "Honoring a Hero."
Head to Western Plaguelands (you can ride north from Southshore into Alterac Mountains, then take the eastern fork into W.P.) and get the Flight Path at Chillwind Camp.
There are various ways of getting in -- some suggest going north around the town of level 50+ mobs, some say just keep going through death and armor breakage. I kept to the hills to the south (level 39) on my mount and only aggroed two mobs, but I lost them by the time I got to the tomb because I kept running. That's my path in the image. Didn't take very long except for the pulling my hair out over all the conflicting directions on Wowhead.
Use the item on his tomb and return to the guy at Ironforge.
Head out front of Orgrimmar and talk to the guy. Pick up "Honoring a Hero."
Head to Ashenvale (follow the road north out of the Barrens and then east along the southernmost range; if you have the Splintertree Post flightpoint, head southeast on the road until you get between the two rivers and then go straight south) and you should hit a bunch of level 30 demons -- look for a path going south into the mountains with more demons and head in there. Take the western fork to its end.
Use the item in front of the monument and return to the guy at Orgrimmar.