You're all wrong! Wrong, wrong, wrong! It is either my way or no way at all!
That having been said... if we are talking about supports that are similar to those seen in either the briefing room or cabin sets, then I don't see a problem with that. Those wouldn't seem out of place as they appear in other areas of the ship.
So a quick modification and a quickly drawn support beam structure (which is in no way the final geometry of them) yields this...
As for the previous image... yes, I know the tables were a little big (it was just to illustrate the idea). And as for the geometry of the dorsal... I'm currently using my 3 foot Enterprise's dorsal as I haven't finished my studies of the 11 foot model yet. But the differences are such that I'm quite comfortable using this dorsal without a loss of generality in these early sketches.
I like the idea of putting guest/VIP cabins in the dorsal because it adds additional justification for the large amount of windows on the surface.
Oh... and yes, the restrooms are one deck down. If a turbolift isn't there in an emergency, you can always use the ladder to get down there.