Without running in NWN server, your going to run in to problems in multi-player. That is why there is a NWN server program. The mod you are playing could be set up for multi play in a couple of hours in the toolset. (probably less) As of now, it is ment to be a solo play mod. So you are fighting the mod, and NWN by hosting for MP via the NWN main. You can save via NWN server, in fact you can set it to save automaticaly every minute if you wish. Once saved, you can load up the sdaved mod from NWN server, it lets you see saved games as well as the Mods in the Mod folder.
Window mode is the prefered method to switch screens, and in window mode you can still play full screen.