However, I have read both (several times) and seen both (several times), and I definitely appreciate Big Sur over On the Road as a film adaptation. I'm not sure one is more filmable than the other, but with Big Sur they seemed to capture the essence of the book more accurately. Maybe it was the casting (way better Kerouac, very good Neal and Carolyn, great Lew Welch), or the general ambience, or the voice-overs from the book, or the gorgeous scenery...
...or maybe it was just Kate Bosworth.
In any event, what did you think of Big Sur the movie? I liked it.
P.S. We have airline tickets for California this summer and a couple of nights in Big Sur is on the itinerary (if we can find an affordable place with available rooms).