I've got no idea if this works with horde, as I don't actually have one at 80 to try it with.
1. Go to Krasus' Landing (flight place) in Dalaran
2. Get on a flying mount
3. Fly over the wall leading to Sunreaver's Sanctuary (horde place)
4. Find a place that you want to be in the territory, and stop moving. Do not dismount.
4. Let yourself be dismounted from the restricted flight area debuff and parachute to the ground.
5. Watch your step!
Stepping on the red tile road gets you thrown out seemingly, but stepping on the white tiles doesn't. You can also go inside "The Filthy Animal" which is, I'm assuming, an inn.
It is possible to move around, but you do get thrown out if you take a wrong step, I'm not really sure what causes it.
You can also move around completely in the inn.