Any spreadsheet will do the first, if you have any inclination to formula building at all. Simple stuff, really.
The second part is harder, because it qualifies as an "art". Without inspiration, either yours or someone else's, exterior views and deckplans are rarely going to satisfy, regardless of shiny presentation.
Inspiration comes in many forms, of course. It could be a Google Image search, a favorite movie, an existing deckplan that gets you thinking "if only they put that *over there*", or a previous edition of Traveller's list of hull configurations and what those mean for dimensions. Yes, it used to be much more complex...