I have to agree with Christopher, regarding the Raven... I seriously doubt it was a genuine Starfleet design. I prefer to think along the lines that it was a small "research" type ship, that Starfleet was loaned by some academic institution, like the Daystrom Institute, or the Vulcan Science Academy. Personally, I think that makes more sense.
That's getting it backward, though. The Raven
wasn't used by Starfleet. It was manned by two civilian scientists, Magnus and Erin Hansen, who had their daugher Annika along with them. And yet its consoles and display graphics were standard Starfleet-issue stuff. If anything, it looked like the opposite of what you're saying -- a Starfleet-built vessel that somehow ended up in civilian hands, after being decommissioned, perhaps.
And if you look at its MSD
, the thing is five decks high and clearly designed to accommodate a crew of maybe a couple of dozen, so what was it doing with only three people aboard? That just reinforces the idea that it was some kind of Starfleet hand-me-down that somehow ended up in the Hansens' private possession or use.
The "passenger train" idea is an interesting one, but I think the ship would be a little wider than that. What I'm imagining is that it's wide enough for a narrow corridor with compact, maybe Defiant
-sized staterooms on either side, but that areas like the lounge and lab would be pretty much full-width. So in the deck-1 plan I'm imagining, you'd have the bridge/cockpit in front, then maybe a short corridor with storage space and a stairway down, then a door leading into the lab area, and then behind the lab would be the medical bay on one side and the transporter stage on the other with an open passage between them, leading to an open area in back with engineering consoles and maintenance access as well as storage. Maybe a second stairway coming up next to the medical bay. And then below you'd have the nav deflector and sensors taking up the forward space, then the bottom of the stairway, then a corridor with quarters on either side, and behind that the lounge/mess area and the head, then cargo storage behind that.
On the lifeboat question: could the staterooms themselves double as lifeboats? I think that would save space.