As always, Mark Bremmer's VTC tutorials have lots of info.
When you select the tools in the terrain editor, you can change the size and strength of the effects. It is one of those things that gets faster with practice, but I agree it is clumsy when you have a specific terrain feature you want to emulate. I am going to experiment with the Digital Carver's Guild plug-in that uses real topo maps.
The Bryce interface used to be almost the same as the Carrara interface in the terrain editor. You might as well stick with carrara.