I am pretty sure the forum never needs more than 400px, although it looks best with at least 600. (I think most forums are like this too). If it is taking up any more than 600 I am pretty sure you need to change your skins ContentPane to handle this.

There are 3 basic browsing views of this module: Groups, Threads, Posts. The initial view is (Groups View) so to go to Threads that is one click. You then see (Threads View) with a series of threads and click a single thread name to see the posts view. You could have also clicked "New Thread" button to start a new thread/topic. This is click two. At this point (Posts View) you can either start a new topic/thread, or they can reply to an existing one, which is three clicks. This is how all forums work. (Basically) Its a hierarchy thing.

It sounds to me like you really need more of a Blog module. The blog module allows a single person to post a topic, and then comments based on that topic are an option. (This also controls time on/off which you cannot do in the forums as of now, in the future this will be an option based on skin objects you use but thats a whole nother discussion)

As for your sites concept, I am not even sure what you mean. Do you mean you are basically using this website for marketing purposes with the hopes of two different networks being your primary target?