I've got a few things to do with terrain sculpting rough-in first before I can smooth things out and detail the terrain.
Things To Do
Rough sculpt the terrain.
Smooth the terrain out.
Work on the terrain detailing.
Paint in routing for camera and Sims.
Start painting the terrain for the riverbed and just take it all over.
Start laying down the roads and trails.
Place effects.
Place Road Objects.
Start painting the desert terrain over the riverbed paint.
Paint in the grassy terrain in the spots meant for grass terrain paint.
Place spawners.
Place world objects.
Prepare world for export to game for testing.
TODAY'S PROGRESS
Here's the outlining I started with to get more raised terrain.
http://farm8.staticflickr.com/7296/12364914703_773200256c_z.jpg
I've raised more terrain here.
http://farm8.staticflickr.com/7349/12364759165_360d2af65f_z.jpg
I've gotten most of it filled in and started another level around the outside edge.
http://farm6.staticflickr.com/5542/12365209114_a3512369b6_z.jpg
I've gotten most of today's work done.
http://farm3.staticflickr.com/2885/12364769425_e8de399184_z.jpg
Here's my saving with "save as" and using new file names each time I save.
http://farm4.staticflickr.com/3810/12364773075_a5a61888b6_z.jpg