If I were making this decision, and none of the players had read the novel, then I would consider both the issue of railroading, and the issue of spoiling the book for them. If it were me, I would prefer to spark their interest in reading it. That puts me on the side of creating a path for the characters that is unrelated to the story told in the book(s).
When in a situation where I will be running settings tied to films, or books, or that have invasive metaplots (Star Wars, Neverwhere, Serenity, oWoD, etc), I have two approaches:
Approach 1: Normal Workload (Just using the setting)
I try to run things the same way I would run a game without a strong primary story: that is, I would put the focus on the story of the PCs as if it were the primary tale. The story from the novel or film is placed in the background as extra detail. The events in the game may or may not ever involve the events or characters of the original source material - and I would work to keep them separate if at all possible.
The goal of this approach is to create unique adventures in an established setting that all or part of the group enjoys, without worrying about existing story lines. This can be done by simply ignoring/deleting the original story, by avoiding it by setting your stories in another time or place within the setting, or by creating unrelated plot threads with no crossover with the original story and making them the focus of the campaign.
Approach 2: High Workload (Creating subtle links to the Original Story)
If I have the time, or motivation from the players to allow their characters to get involved in the primary plots from the original source, I like to remember that historical records and memory are very selective. That perspective is the tool that I use to create subplots and important interactions with the main events, which do not threaten or change the continuity of those events.
This sort of thing involves approaches such as providing roles for the PCs which make the tasks of the characters from the original source material possible. Without the PCs' actions, the course of events in the source become impossible.
example: An information gathering quest for beginning characters
An advisor to a character from the books reveals information about the enemy, a prophecy, etc in the original storyline. As I am looking for neglected or glossed over parts of the story to flesh out, this sort of scene might catch my eye as an effective way to introduce starting characters, and enable the players (who may not have any familiarity with the sources) to establish an understanding of the setting and culture being portrayed in the campaign. To make use of it, I would:
- Create a plot where that advisor had recruited one of my NPCs to uncover information in an earlier time period.
- That NPC would then select the PCs and send them on a dangerous journey to collect that information
- Use this to establish the skills and personalities of the characters, connect them in a very tangential way to a peripheral character in the original source, while at the same time making them a vital, but invisible part of the original tale
Doing this for the course of the series, will take a great deal of familiarity with the original work, and a lot of planning to find ways to have the characters support the main plots of the source material without ever being 'deemed by history' to be a major character in the story.
The goal of this approach is that when the players read the books, they can get an extra smile and surprise when they realize their hidden role in the tale that is unfolding before them.
I am the one who brought Sir Fancy-Pants the news that the Dragons had awakened! I almost died that day...