Excellent news, really. It turns out that not all of the introductory history was all that hard to fix. All I had to do was cross it out and write "Then, several hundred pages of irrelevant tangent happened."
It was so easy. Less sarcasm involved, of course, but there are worse things in life.
Here is my favorite of those pages:
Roran married Katrina, who was pregnant. For the first time in a long while, Eragon was happy.
Then Murtagh, Thorn, and a group of Galbatorix'smen attacked the Varden. Again. With the help of the elves, Eragon and Saphira were able to hold them off, but neither Eragon nor Murtagh could defeat the other. It was a difficult battle, for Galbatorix had enchanted the soldiers so that they felt no pain. The Varden suffered many casualties.
Afterward, several hundred pages of irrelevant tangent happened.
Roran served alongside the Varden, and he rose through their ranks, for he proved himself a skilled warrior and a leader of men.
Then, more irrelevant tangent happened, and Orik was chosen to succeed his uncle as king.
Eragon and Saphira returned to Du Weldenvarden, because they really liked flying back and forth from one end of an enormous, enemy-occupied country to the other.
I also rather liked this bit:
Because, I mean really, Murtagh had them beaten. Why the heck did all the bad guy armies just up and leave? Maybe I remember something wrong, but whatever. It still seems arbitrary.