I’ve found the portrayal of women in the novel to be interesting in that they seem to be only mentioned when they are someone’s mother, are sleeping with someone, or someone wishes to sleep with them. Kerouac lauds many of the men in the story (i.e. Neal, Mississippi Gene) and elucidates a great love for them, but he does not devote the same attention to women. There is the distinct sense that they are unequal to the men, and they remain flat characters in relation to the male ones. However, he does not express any explicitly misogynistic feelings, which makes it unfair to label his vantage as sexist.
I found an interview with Joyce Johnson, a beat author and girlfriend of Jack Kerouac when On the Road was published. Of course, her comments contain her own biases, but I think she makes several points that provide insight into Kerouac’s relationship to women. She speaks of his relationship with his mother, which she posits hindered his ability to participate in a real relationship. Additionally, she speaks of the cultural norms at the time and gives a cultural context in which to place the casual sex that occurs in the novel. Here’s the link: http://www.guardian.co.uk/books/2007/oct/12/fiction.jackkerouac