It's a foreground of my feeling. That place moves me. And I don't mean my country; it's part of our shared natural world that happens to be particular to a sense of wherever my storytelling inclinations come from and my own history of kind of being a road rat and travelling.

When you act in a film, you're inevitably surrounded by people you didn't choose, right down to the set painter. I like being able to pick the family I'm waking up to in the morning that's going to make this group effort to tell a story that applies to what's interesting to me at that stage in my life.

Well, it was interesting because when I was going to do it the first time in my head was Leonardo DiCaprio [for Chris] and Marlon Brando was going to play the character that Hal Holbrook eventually played. But then when it wasn't to be and there was no promise that it ever would be I think some part of me didn't want to attach specifics to it anymore - actors or anything else - because I wanted to see it made that much more badly.

I've been a road-rat since I got my driver's licence at 16, so I've probably gone across America 20 times.

The heartbreak that it might not happen wasn't something that I wanted to face with any more weight. Then, when I got the call to go ahead I never thought for a second as I was approaching it who I would get - that would come later. Again, I think the idea was that I now had the rights to make the movie and I can start writing it but if I have to wait another 10 years before I find an actor that's right for it, I'd be very happy to do that.

You're always having to live more to fuel something new. It's an obligation to yourself and to the audience. The personal baggage that comes with being a known actor just adds to that struggle.

Well, the kind of central question: "Do you want to live - and I don't mean stay alive - do you want to feel your life while you're living it?" You know, there's somewhere to go that was here before we were and is going to be here after us, so get out there in it. It doesn't take somebody who's got some self-important sense of their own attachment to nature to recognise that you're just stupid if you don't go out there.