I started an Internet search for British 1930-40s coastal freighters to get some inspiration and plans. During my search I came across some interesting stuff, such as the U.S. Navy book on Merchant Ship Shapes and plans for a coastal tanker that look a lot like the Warlord Games merchant tanker, but I didn't find any good plans for coastal freighters. I did come across several photos (1 and 2) and decided to base my ships on those, while using some "artistic license" for the details. I decided to build one ship with a center bridge and two with aft bridges.
I started out with basswood to make the base shape for the lower hull and then started adding balsa to build up the forecastle and superstructure. I'll use some sheet styrene for thin flat areas (like the decks for the bridges) and ship sides. The ships are almost 7 inches long (like the cardboard counter frigther stand-in included in the starter set).
I'll post some more photos when the ships are done.