Neverwinter Nights 2 Interview is offering up an interview with several members of the Neverwinter Nights 2 development team about the RPG sequel's multiplayer functionality.
Q: Can players run through the single player game and then transport their characters into the player created content? If so how does this impact the game?

A: Similar to a Paper & Pen game of Dungeons & Dragons, the player can take the character they created into the Neverwinter Nights 2 Official Campaign or most any user-created modules. Using the Export Character option the player can save their character in its current state and then use that character for a new adventure. Obviously if the player Exports their level 19 Warlock and starts the Official Campaign from the beginning with that character, the game will be pretty easy, but players always have that option.

The Toolset allows users to put in custom restrictions for their own modules. For example, if a module is designed and balanced for level 10 characters, and the players starts the module with a level 1 character, then the designer of the module could choose to give that character enough experience points to level up so that they are more of a match for the challenge of the module.