You might want to look at MLCad and LPub as a better set of tools for LEGO design and publication of instructions than LDD. MLCAD and LPub are freeware and work very well for even very large models. And they support many, many more LEGO part types than LDD does.
There is also a book published by Syngress, "LEGO Software Power Tools" that describes how to use these and other tools. The ISBN is 1-931836-76-0.