Ozmac ;
You have a very good start in the right direction . Just remember stop when you think you should ! You will figure things out . A tip here :
When you add the portholes then take the rusting agent and do this . From the top let it run around and freely under the rim . if you want the deckhouse grungier then find seams and rust them up with emphasis from halfway down for the heavy rust .
I did notice on my boats the join between the cabin and the deck were always needing attention and my boats were only six yrs old . Ah Yes , water , water everywhere and not a drop to drink , Sure does like to rust me boat though , I think !
I have one more suggestion , if you don't mind .The entry to the Wheelhouse is not there .Can you take some .010 sheet plastic and make some doors ? And put a small port right in top center .The Despatch # 9 Tug had the same deal . Nice wheelhouse , no way to get in there though
Polished cardboard works too .You might find a mailer that has wood grain on it , made of heavy card , use that ! I always use stuff like that . Saves on scratch - building , and painting ! .