Enhancement request. DL could you code a button in DMP menu that says "Save Current Connected Universe as offline savegame?" and then prompt the user for a savegame name, which then generates a savegame folder, persistent file, and all craft files both locally in the user's DMP savegame folder, and all craft files in the craft file library on the DMP server. This saved offline version of the DMP universe would then be immediately accessible in KSP.

This is already kind of available, Start game -> DarkMultiPlayer, it should show you your last connected universe.

EDIT: The saved crafts are not. If you'd really like this feature it would be easy enough to implement, even in 0.1.6.x series.