I'm trying to village with a river running through it. I'm modifying the "Empty World" worldspace, since I'm just trying to do a little self-contained thing. Is there any way that I can put a river in without just editing the land height down drastically? The problem is that not only does the river end up looking more like a canyon with water in it, but I also don't seem to be able to edit the height near the edge of the worldspace, so I can't make it run all the way across.

Also, while I'm asking questions, is there a better way to change camera angles when doing landscape editing then to just plop an object down in the midst of it, select the object, and spin around it? Without an object, the camera tends to fly away, but it seems like there ought to be a way to fix the camera on a piece of land/cell itself, rather then an object in it.

Perhaps another way of thinking about this would help: suppose I wanted to make two rivers at different elevations. How would I do that?

I think someone actually created a water mesh that you can use to fake a river from a distance, but if you want it to be swimmable water, then you can only have one water height for the entire cell.

You don't have to drop the ground level, you can raise the water level for a cell. Default is no visible water, by having it down a long way, so you need to bring it up when you want to have a river. There are limits on how steep the ground can be, which is why you have the edge problems - the CS assumes the adjacent cell is at normal level. So raising the water level will cure both issues.

Two levels of water in a cell does not work, but adjacent cells can have different levels - waterfalls are placed at the cell boundaries.

And, in comparison to how it is in reality, rivers are usually always either at a lower level than the surrounding terrain, or have waterfalls and rapids where the height of the ground changes. Only floodways and washouts have a particularly steep slope, and that's mostly because those are temporary features.