The raised aft end (behind the triangular projection) is actually the auxiliary craft landing bay. On the top view you can see the faint outline of the three-panel bay doors.
Something else I think I've managed is a design more rudimentary looking without being overly clunky and awkward. I'm not going to define every single element within the design, but I am trying for a concept where some machinery looks exposed (without having to actually name what you're seeing). This will be particularly true on the underside (above the nacelle) which I haven't tackled yet.
I might do a rudimentary cutaway/deck layout to get a better sense of scale for the purpose of getting hard dimensions. Eventually I'd like to work out a loose backstory. ship capabilities and perhaps even a list of names.