This is the earliest manuscript outline that Martin sent to his publishers. It changed DRASTICALLY in later drafts and has little resemblance to the final version.
Keep in mind that even, say, in Tolkien's The Lord of The Rings, "Strider" (Aragorn) started out as a Hobbit named "Trotter" who had wooden feet, because he'd been a prisoner in Mordor for a while and had his feet cut off. Tolkien had no idea who Aragorn was and it just popped up as he made later and later revisions. Also in the original Lord of the Rings outline Aragorn ended up with Eowyn, and Arwen didn't even exist. In later drafts he realized that Eowyn's love for Aragorn was really obsession, and she ends up with Faramir (both actually have a lot more in common, being the unfavorite child in their families).
Martin originally planned the story as a simple trilogy: what became the third novel, A Storm of Swords, was really the end of the original "Book 1" - after which he intended a 5 year time jump (like 20 years or something pass by the final novel in his original concept).
So if we think of it as Classic Greek Theater structure, the death of Joffrey and Tywin is the end of "Act 1 of 3".
The original draft outline basically has a straightforward war between the Starks and Lannisters, with the Targaryens in Essos, but not even mentioning the other major families. All of the subplots about the Tyrells, Stannis and Renly Baratheon, the Greyjoys, the Martells - all of that came in later revisions.
Again I must stress that this was the most bare-bones outline and changed to the point it was almost unrecognizable:
- In very early drafts, Martin thought that Sansa wouldn't just choose Joffrey (when Cersei arrests him on charges of treason), but "choose Joffrey" by marrying him and bearing him a child, and only then learning how crazy he is. Makes sense if you think that actually some years pass, or Sansa is older to begin with, so she marries Joffrey not knowing who he is.
- Jaime Lannister is more of a straightforward villain, one of the main villains. In the final version, he's actually a tragic, conflicted figure who actively avoids political power because it disgusts him.
- Robb Stark would have maimed Joffrey Baratheon on the battlefield, but ultimately Robb would die in battle to the combined strength of Jaime, Tyrion, and their allies. It would be Tyrion would would besiege and burn Winterfell.
- Arya doesn't get separated after her father dies; instead she flees along with Catelyn to the north. When Winterfell is burned, Catelyn flees north along with both Bran and Arya.
- ...The Night's Watch is politically neutral so Jon can't shelter them there. This causes a rift with Bran, but Arya understands. Moreover, Arya realizes that she has fallen in love with Jon, even though he's sworn to celibacy. This passion would torment both Arya and Jon throughout the trilogy.
- Catelyn, Bran, and Arya would flee north to Mance Rayder's camp, and they'd join them in trying to fight and hide from the Walkers, but ultimately Catelyn is killed by the White Walkers.
- It appears that the Red Wedding wasn't thought up yet. GRRM wanted to subvert fantasy narrative cliches: the idea that Robb would fight Joffrey in an epic battle face to face. In the final version both are killed through treachery and not in battle.
- Daenerys doesn't support Drogo killing Viserys; instead she bides her time and eventually kills him to avenge her brother. She then flees into the wilderness where she *finds* dragon eggs. The Dothraki fear only two things: the ocean and dragons. Riding back to Vaes Dothrak on a dragon they are over-awed and instantly submit to her will. Uniting all of the Dothraki for the first time since the Doom of Valyria, Daenerys begins to plan to invade Westeros.
- Tyrion would actually kill Joffrey in disgust, for the good of the realm, when he realizes how utterly crazy Joffrey is.
- ...SOMEHOW, Jaime Lannister would succeed Joffrey on the throne, by virtue of killing everyone ahead of him in the line of succession (Jaime isn't even IN the line of succession in the final version). Jaime also blames Tyrion for the murders. Once in exile, Tyrion changes sides, making common cause with the surviving Starks to bring Jaime down, and falling helplessly in love with Arya Stark while he's at it (keeping in mind that many years have passed since the beginning of the story). This leads to a deadly rivalry between Tyrion and Jon Snow over Arya.
So this changed so drastically from the final version that it's not really a guide to anything. Daenerys never even goes to Slaver's Bay in this version. A Jon Snow/Arya/Tyrion love triangle? Jaime as a primary villain? Apparently no mention of Cersei?!
He apparently always considered the "five main characters" to be Jon Snow, Arya Stark, Bran Stark, Tyrion Lannister, and Daenerys Targaryen. I guess later drafts would add this up to include Jaime and Cersei -- in the TV series, by pay-grade, the "Category A" "main cast" (if there could said to be a "main cast") are the three Lannister children (Cersei, Jaime, Tyrion), Jon Snow, and Daenerys Targaryen. And yeah Arya and Bran are also important but something about child actors getting paid less.
So don't really take any of this as a guide: MANY major characters didn't exist, even Cersei barely figures into it, Jaime is a straightforward main villain of the story, etc. etc.
Though the part about Dothraki practically worshiping dragons with fear...