Might I suggest you take a trip down to your area toy store and take a look at the diecast cars and trucks, you’ll probably find a pickup with a boat and trailer. These are also very close in scale to your HO project.
I’m just starting this kit. Bought it at the memorial 20 years ago. Being new at this I’d like to know how you did the deck? It looks great and I’d like to include that in mine.
I do have to remind you, the pictures shown are of outboard NOT seen very often nowadays . You could go to your local model railroad store or walther catalogue and find newer ones, if not you would need to modify the engine casing to reflect an engine from 1959 and upwards .The lower end would need just a mite of update. . My suggestion , find a neighbor who has a 14 to 18 foot fish boat and check out the engine and you,ll see what I mean . good luck on the project . tankerbuilder