It sure seems like the access to the pylons would be much larger, but I can see how the TV show budget would keep the Jeffries tube pretty small. I choose to believe that it IS access to the pylon and if you were to climb high enough you’d reach the nacelle.
I enjoy the idea that the interior proportions of the Enterprise are so wildly different from the exterior that Scotty can have his toes visible from the corridor and his head duly inside the nacelle. I’m not saying that’s your take, just thinking about the notion.
TV show practicalities are why I presume the decks aren’t actually 10’ - that’s just a reality of filming. Same with the slightly underside shuttle exterior vs way oversize interior. But my interpretations aren’t correct, there are no correct interpretations, just interpretations. 🤷♀️