How to make labeled curved text?

[J.Edward]

In photoshop the easiest way would be to use the freeform pen tool if you use a graphics tablet.
Just draw the curve along the river as you like.

Then select the type tool and click on the curve path you just created.

If you aren't happy with the curve path you can left click the type layer and the go to edit>transform path>distort and play around with reshaping it.
It won't appear that the text has changed until you accept the transform operation.

You can get a lot of variation that way.