Anyone know where I could get the full documentation and back story supplements? There seems to be alot not in the GoG manual.

I have the original manual (sans cover), I could scan it for you. It isn't particularly lengthy though.

Fron TV Tropes: http://tvtropes.org/pmwiki/pmwiki.php/Main/TotalAnnihilationKingdoms

All There in the Manual: The manual, that is, and also a lot of background information in the form of HTML files on the CD. Those who read it all were surprised (especially given the previous Total Annihilation's scant storyline) to find that the background of Darien was at least as well developed as WarCraft's Azeroth was at the time.
One story in particular deals with a Verunan sailor who explored Zhon looking for a MacGuffin and managed to defeat three Jungle Orcs and a Shaman using only a sword; those who know those units' capabilities will immediately mark him out as a true Badass Normal.

I'm kind of keen on finding this supplementary information. There's stuff on the manual but all i've managed to get is the world map, and the GoG manual.

I thought you meant the original, not Kingdoms. Please specify in the post title next time.

Ok, I specified in all my other posts. I just forgot here!