I been looking for a while for one that covered everything from start to finish, I checked the course on the architectural design but I feel I need more especially on organic things like rocks trees terrain and so on.
Hey elfideo , that is definitely on my to-do list! I have a few other things to do in-between though, so it may be a bit before I can tackle them. In the meantime, I'd recommend checking out the Grove addon for trees. It's up there in cost, but well worth it from the results I've seen so far if you plan on doing a lot of environments. https://www.thegrove3d.com/
While we don't have big environment courses we do have a few that could help with building organic plants: Creating Grass in Blender and Creating Plants in Blender.
I would really like something like a Terragen 4.0 course, that explains why some things should be done some way and not another. Something I find the few tutorials out there severely lacking. This would integrate perfectly with other Blender courses like rocks and trees, that could be used as populations...
One man can dream!
There's also a software called TreeIt! It's a free standalone foliage tool that's pretty great and can do a lot of stuff http://www.evolved-software.com/treeit/treeit
One thing I've wanted to use and teach in courses is SpeedTree but unfortunately you can't distribute models that you create within SpeedTree.