I've often said that the problem with comparing the unfolding of the lives in D&D to a novel is that roleplaying the life and times of adventurers lacks the common cohesion of theme and structure that novels seek. If the progression of a D&D can be compared to any kind of novel, it is the picaresque alone. The more I considered that position, the more I realized how well it fit. Indeed, the term itself comes from the Spanish "picaro," meaning rogue.
Let us take some picaresques as consideration—Barry Lyndon, for example. Redmond Barry is a self-serving "adventurer" who fights in a duel, runs away from the law, joins the British army, deserts the British army, is press-ganged into the Prussian army, becomes a police spy in Berlin, turns into a gambler and cheat, and then marries wealthily enough to hope to obtain a Peerage back in England. Not bad for a man of humble country gentry means. What I'm interested here is the amount of deceit and underhandedness as well as the apparent social mobility of the picaro. These are adventurers in both senses of the term—the commonly accepted one and the one popularized by D&D. While there are plenty of upright and noble PCs, they are more often than not cast in the role of the picaro.
The adventurers of the picaro tend to look something like those of the average D&D group as well. They get into episodes of trouble and either by luck or cleverness they weasel their way out. They search for money and status, cross class boundaries with more ease than the other members of their society. They're generally social outsiders, as adventurers are bound to be.
The main reason that picaresque comes to mind when talking about D&D (or many other roleplaying games of the same type) is because it's generally episodic. One episode occurs and then is followed by another but they aren't connected by a larger set of themes, much like one adventure and another. Certainly there are causal relationships between adventures, but they make a very loose tapestry of cause and effect. Yet somehow, the picaro and the adventurer share more than just this narrative structure, this "episode of life" storytelling. Perhaps it's because of the way The Dying Earth was written (particularly Cugel's Saga) or perhaps it's just a result of the structure, but I'm of a mind to think that it has something to do with the relationship between pulp fantasy and picaresque.
Many picaresques are in first person (like a roleplaying experience), about devious or cunning characters, deal with those who are forced to survive on luck and wits alone, who get into and out of trouble frequently, who break social conventions and boundaries, and whose lives are eventually about adding up individual episodes together. Is D&D not the perfect picaresque? It's hard to say if it was designed to be, but it certainly appears to be made for it.