Well, I don't think it's ever going to be "proven" one way or the other, since there's no official answer.
I really think you should read this article and take a quick look at the screencap from "Day of the Dove" at the bottom. Bob
Thanks man! I appreciate how thorough you were with your comment. I have to admit, I prefer Season 1's set design compared to Season 2. I just have a bit of trouble seeing the secondary hull deck layout of the TOS ship being circular, as opposed to the Galaxy-class, which if I recall correctly from my blueprints, had decks lining the exterior and interior, with a comparatively angular deck layout. But, to each his or her own.
@ Admiral Archer You wouldn't be the first having that kind of trouble, but I just couldn't ignore the scenes from the beginning of "The Ultimate Computer" and others which exactly do suggest this. Interestingly, I do have this highly detailed Galaxy Class cutaway where the artist apparently (but erroneously) concluded from the actual studio set plan that the TNG engine room should be close to a circular structure (i.e. computer core) - which curiously was the major inspiration to apply the basic thought to my TOS Enterprise deck plan proposals. @ FalTorPan I agree, because in my deck plans the ion pod will be at the bottom of the engineering hull and the bowling alley probably in the connecting dorsal. Bob
I voted in the nacelles; because that's what I always thought when I was watching it growing up. What I saw gave me the distinct impression that the antimatter pods (which presumably contain the antimatter), the reactor and the warp apparatus were all in the nacelles. Why else would the Jefferies tube be at an angle? It goes up the nacelle pylons to get to the warp reactor. When I got older I thought that maybe it was a bit more like the NX class (although this was way back in the 90's, well before ENT), except the reactor was really big so they had built it under the floor. But thinking about it again now, I see no reason for it not to be like Matt Jefferies originally intended. I can even buy (just) the big red V8 powered by lightning we saw in TAS (can't think of the episode right now) being the warp reactor. There could well be a third reactor, perhaps powering the rest of the ship when the engines are on tickover, but I'm not sure - that seems a bit convoluted. Surely impulse (i.e. fusion) powers the rest of the ship. I think that the Engine Room we saw on screen is either right in front of the impulse deck (making the big triangle tube setup part of the impulse reactor), or in the secondary hull, about where the new cargo bay was in TMP (making the tubes some sort of power converter, perhaps taking excess warp power and converting it to mains electricity). I don't think that it is akin to the warp control monitoring room from the Enterprise D for a couple of reasons: a)they'd be in a fairly inaccessible place, b)they'd be duplicated in each nacelle and c) there is a corridor outside that can't fit in the nacelles. That said, I have no problem with there being more than one engine room, perhaps having an impulse one and a warp one. you'd just have to explain which you wanted to the turbo lift each time.