Thanks fellas.
Frames are about 10 mins each at Q=0.7,AA=3, GI 2/4. I don't think this needs too much AA, the last frame was rendered at Q=0.8, AA=6, GI 2/4, but I don't think I'll need to dial that for the final render.
The camera curve is going to be a challenge trying not to make the last 4,000m last 2 frames, due to the distances. So this will dictate how long the animation needs to be. I've also got about 100km of Mars Dem in that scene to fly around if I want, but the main thing is to see if I can get a good stereoscopic render from it with two imported cameras.
It would be cool if I could adjust the camera positions and rotation with functions to make this last part easier, by setting up a rig.