What if you set up a series of empties, cast vectors between them and the player, find the shortest vector, and apply force along it?
It’s not a perfect solution. It definitely wouldn’t scale up well, imagine 50+ points to calculate each time. Also, now that I’m thinking about it, if you dropped some rigid body spheres on the map, they’d probably start pooling towards the empties. I guess I’d have to set up a demo and experiment with it.
I’m sure there’s a better solution, though.
Hmm… I think the way to go would be to use rays infront of the player (and at his feet), if the ones going straight ahead (or at an angle) at his feet collide with the ground… it’s time to rotate the body until the ray pointing at the ground detects the angle.
I know it sounds confusing, I wanna whip up a blend soooo bad, I’m working now… maybe tomorrow I will 
Are you using the “mouse look” script?
Because I used, but when I’m on half the planet, the camera tends to turn upside down.