The Lord of the Rings: War in the North Developer Blog: Challenge Maps

The Lord of the Rings: War in the North lead designer Andre Maguire brings us a new blog entry on the game's official website that describes the mechanics behind the Osgiliath and Lorien challenge maps they'll be including in the game. Additionally, he reveals that these were originally going to be used as pre-order bonuses, but they've since opted to make them available to everyone:
These maps are accessible from the Middle-earth map at any time once they are unlocked. You can choose either of the two challenge maps to start with.

Each map will display level recommendations for player characters; after all, we want to make sure you're ready for the challenge!

'¢ Osgiliath is recommended for players who are level 4-16
'¢ Lorien is recommended for players who are level 11-22

Challenge maps are a great way to get bonus XP, loot, coins and achievements! Upon completing each of the challenge maps you will get a lump sum XP bonus on top of any bonuses you got along the way!

You can use the Fellowship symbol located in either of the challenge maps to return to town any time during the challenge should you choose to exit, so you won't have to lose your place in the story, either.

Also the original plan for the challenge modes was that they would be available to only pre-orders. However, after seeing the passion from the Community and Fans for this mode of play, we have decided to put them on disc for everyone to enjoy!