As far as the Captain's Yacht goes, there were pressing reasons to show or mention it in episodes like "Samaritan Snare", where it's a big deal the Captain goes on a personal ride. It was not shown or mentioned. So we either have to invent an explanation that allows it to exist but be unavailable, which is fine if we want to believe in it existing for some other reason (but there is none), or just abandon the idea altogether.
(where the Viceroy dies by falling down into an abyss... from the 29th deck.)
Why would he stay on Deck 29? He was going to abduct Picard, who was on Deck 1. He walked to his meeting with Riker, who also walked. So if anything, the action would be on Deck 14 or thereabouts.
Although since the Viceroy was in a hurry, he would not have slowed down to a walk until he was almost at his destination - which might place the meeting much closer to Deck 1. Whereas Riker obviously had no clear idea where the intruders were (battle damage?) - meaning he would have no reason to go all the way down since he'd know the intruders would be coming up at least some
of the way (why else intrude?), but he wouldn't have a good reason to step out of the turbolift at any specific deck as such. So, the question isn't so much "where did the meeting take place?" but "why did the meeting take place to begin with?"...
We might speculate the turbolifts were under the control of the ship's crew and thus the intruders were forced to use the corridors - and further that the corridors were locked in a way that forced the intruders to a confrontation at a specific location. That would be Internal Security 101, really. But that makes one wonder why the security officer pressing the appropriate buttons did not also activate forcefields that would trap the intruders, deploy stun gas, or evacuate breathing air. If "battle damage" is to be our answer to all these questions, then "battle damage" would also be the reason both the villains and the heroes walk all the way - hence they meet on Deck 14.