So, I was thinking designing a level/map with 2 different areas, a forest and a desert. Is that possible without making to different landscapes and making the players go through a load screens?
Heck yeah 
You can have your landscape material have all the paint layers you need for both terrains, and divide wherever, however, on your landscape. You can even split where your sand dust particle starts and stops with volumes. Sounds can be spawned accordingly as well.
If what you are talking about is having 2 landscapes in the same map you should look into level streaming, where when you come close to the end of one landmass you could load another one in.
I think he wanted the easy solution. He mentioned not loading with just one landscape. If I’m correct, Level streaming would want 2 landscapes, and if not, than it would want spilt components which may not line up with his desert/forest divide. Though I absolutely agree with using Level streaming. It is on the more performant side.
Yeah I tried that but don’t I need to first fill the landscape with one layer first? I tried the forest part and used grass and dirt, and every time I tried painting on with grass on the dirt it just resulted in the grass being overlaid onto the dirt and not actually appearing as grass. Was that something wrong with the material layers that I made?
Sorry, still new to this whole stuff.
Looking into level streaming now. But the map that I have in mind is an Island which has both a forest and a desert. Is level streaming possible within a single Island (It’ll be like 9km[SUP]2[/SUP] big)
Yup. Level streaming can handle any size map.
Yeah, fill your landscape with any layer, than paint as you need to. The dirt not being fully over the grass, it sounds like you might be using a Target value?! Use a target value of 0 and just paint normally.
https://drive.google.com/open?id=0Bw0GrwSYliGWc0pXMzRtc2RFTzg (Can’t upload a pic for some reason o.O?) So is this what is supposed to happen? Because I want the grass to be a completely different layer, but instead it keeps getting overlaid onto the dirt… And no I am not using Target value. I did however try enabling it and using it as 0 and paint just now but nope still the same thing.
I actually meant a value of 1 for target value, but like you said anyway, that’s not it.
I see what you’re saying though. This looks like your Falloff value. Decrease it so the brush is bigger and closer to the outline. The is the “Lerp” strength, if you will, of the 2 layers.