I have done whole the FinRus map with that elevation filter and without satellite data, because I was so rookie in that time and didn't know anything of possibility doing elevations with DEM-files!:D
The elevation filter is a good tool if you are patient and have time to learn it. You must use all the time different values with your hill's hight, width and length and "plough" your terrain many times with that tool.
Here's one example. If you want naturally looking hills, use only "Sine Wave". I have assigned there next values: 5300 (Alt Feet = hight) 5.100 (X Miles = width) and 3.750 (Y Miles = length). Remeber to put the crosses to the X and Y cells!
In the bottom there are "Enable Transition" cell and "Number of transition vertices" cell. If yo fill them like I have done, your hills are becoming merged to the surrounding terrain very smooth. You can try different Numbers between 2 - 10 to that number box.
Mark all the four "Apply transition to" cells like I have done, then the smoothness is becoming all around the edited area!
On the right side is one important cell: "Set alt". It defines the base of the hills, in other words: how high is the lowest point of that hill area.
For ex. if you are creating imagination terrains without satellite data, this Setup Filter is very nice tool. But don't make as big maps as FinRus terrain with it. It's a grazy man's job!:D