Caught The Road on Friday night. Like the book, which I found gripping and moving but also strangely unsatisfying, I had the feeling after I was done that there wasn't a whole lot going on beyond some emotional button-pushing on a very primitive level.
It did put me in mind, though, of a movie with very similar themes and tone that I think was far more well-developed: Kon Ichikawa's Fires On The Plain, made in 1959. I would recommend that one (it's on Criterion) above The Road anyday. Or, if you really liked The Road, you should definitely check out FOTP.