I gave up trying to get a realistic fog effect with the Sky Lab fog a long time ago. Big rectangular fog. Yuck. If you like to keep your terrains large (as I do), you can get a fairly good fog effect by using a sphere with a volume cloud texture. In this pic I created a sphere large enough to surround the camera a bit and reach all the way back to the terrain. Then I dropped the sphere to the ground and sized it down from the top only until it was the height I wanted. I also turned off the fog object's shadows in the Materials editor. I think this looks more like real fog than the Bryce fog does. You can place as many of these around a scene as you want for spot fog, and they make good low-lying clouds for your mountains, too.

This is not my "second childhood". I'm not finished with the first one yet.

Time flies like an arrow; fruit flies like a banana.

"I'd like to die peacefully in my sleep like my grandfather....not screaming in terror like the passengers on his bus." - Jack Handy