Plenty of games have acheivements that are simply markers at certain points of the game. The equivalent for AO would be
- Escape from Rupturefarms
- Traverse Stockyards
- Experience Monsaic Lines
- Venture through Paramonia
- Relight all of the Paramonian Temple
- etc
Just walking past a certain background element would be fairly pointless though.
I suspect that the acheivements will probably also relate to number of muds rescued/killed and finding secret areas.