I have recently experimented with Maps Offline but could not get it to show up anything. I found two options of inserting the cache tiles.
1. placing them in User/Var/Maps
2. placing them in private/cache/MapTiles or so

I have done both to see if any produce results without success. Afterwards I deleted all those files again. I suppose that the deletion of the second path lead to my current issue. At the moment, when I start the Maps.app it just stays with a grey screen as if trying to load and then the iPhone reboots. Clearly something went wrong, but should it not just try to recreate the cache?

My iMac is at the GeniusBar for the moment so I wonder if there is a manual way of SSHing in and creating the right directories again. The Folders are there right now but do I need a standard PList or sqldatabase in there?

Any help would be greatly appreciated.