The curious thing is that Kirk knows everything there is to be known about Delta Vega without looking it up. Add to this the fact that our heroes are within spitting distance of the facility after their misadventure. Coincidence? Perhaps not.
The mission to probe outside the galaxy might have involved some logistical preparation. Indeed, Kirk seems to be saying it won't be a one-shot, and may even not be concerned much with exploring what lies on the other side; Kirk's priority is to ascertain whether it's safe to go there, so that others can follow. Quite possibly, Delta Vega might have been established as part of a logistics chain that would allow for Kirk's mission, and for all the subsequent ones.
So, perhaps we should see Delta Vega as the fourth supply stash in Project Vega, akin to what polar explorers have used: a facility offering fuel (those giant tanks) and shelter (the buildings where a simple dusting and flipping of a few switches makes everything inhabitable), and having been established in advance (robotically or otherwise) and subsequently supplied with ore from which the starship fuel (potentially difficult to ship around, or to keep "fresh" for long periods of time) could be cracked, perhaps only as needed, perhaps in a slow and ongoing process.
Yes, the writing is captivating... Save perhaps for Sulu's meaningless and nonsensical contribution.