You'd need more than the SDK, you would need to have an extended knowledge of C++ to be able to make a mod. You would also need good, well thought out maps.

And if it were to be anything like a true lucid dream, you would have to have destructible environments, and Source just doesn't support that, unfortunately.


I'm sorry to shit all over your idea, it's a great idea, but the Source engine is a little too outdated to do anything big like that.