You should use the shader. So you can tell how often a texture tiles over your terrain. So it cannot look "very bad". You can use 3 different tiling textures and a shadowmap with the shader. But you need a blending texture that tells the shader which of the texture should appear on several locations of the terrain. Just paint red and green channels for texture 2 and 3. Blue channel is for the shadow map.

You can scale your terrain in MED to make it as big as you like.

Learn how to create a terrain in Freeworld with Layers and then export this. You will find all what you need.
And shadow baking is a simple click of a mouse in Freeworld.

I think I should make a tutorial sometimes to show how to do all that in detail.