Ok, so, the 430 spoken by the Fireman apparently was a mileage reference.
Okay... I can roll with that, I guess.
But 430 miles from where? Twin Peaks? Where at in Twin Peaks? Center of town? The sheriff's station? The welcome/population sign? I mean, it matters. If you're off by a mile, then that could mean not finding the entrance to the alternate reality (but they did find it, so I guess they knew where to head-out from).
Next question: 430 miles in what direction? North? South? East? West? There are a lot of roads, interstates, turns and interchanges to take in 430 miles. How did they know which way to go? Fireman Mapquest?
Once they were through into the alternate dimension, how did they then know to go to Odessa?
I have questions, though they're probably over-thinking the whole thing.
I'd need to do some rewatching to see how well this holds up, but I've had a hunch that when the giant* says "430," he isn't giving Coop directions on finding this place. (As you say, those would be some awfully unhelpful directions.) I think he was reminding Coop how far he'd need to go to get back. If you know the direction you came from and how far you traveled, you can now retrace your steps.
And the giant's clues are preceded by "remember," as if referring back to something that's already happened: "Remember: that's how far you drove from your starting point to get here, so that's how far you must go to return."
Again, I'm not sure about this at all, and I'm sure you could also argue persuasively against it. But, yet another thing to think about.
*He'll always be "the giant" to me. "Fireman" just doesn't seem to stick.
I'd need to do some rewatching to see how well this holds up, but I've had a hunch that when the giant* says "430," he isn't giving Coop directions on finding this place. (As you say, those would be some awfully unhelpful directions.) I think he was reminding Coop how far he'd need to go to get back. If you know the direction you came from and how far traveled, you can now retrace your steps.
And the giant's clues are preceded by "remember," as if referring back to something that's already happened: "Remember: that's how far you drove from your starting point to get here, so that's how far you must go to return."
Again, I'm not sure about this at all, and I'm sure you could also argue persuasively against it. But, yet another thing to think about.
*He'll always be "the giant" to me. "Fireman" just doesn't seem to stick.
That's a good way to look at it. Sounds as good as anything I've been able to think of!
And, yes, agreed: the Giant. He'll always be the Giant to me.
Fire walk with