Could someone explain the difference between から~まで　and から~にかけて?

That's the impression I got as well. I've never noticed anyone say にかけて, but then again sometimes I just stop paying attention when there is a group of people speaking Japanese.

Haha, yeah...

Fixed, thanks!

I think the difference is only in structure, and not in meaning (in a sense).

In the first example, you're attaching the entire phrase to the noun 地域 - saying 'in the region from Western to Eastern Japan'; if you were to drop it, I think it would translate closer to 'from West to East Japan'.

With the second, it's a similar situation - you simply dropped the 地域 (or something similar) because it's understood within the context of the sentence. the にかけて phrase is simply assigning a location for the second half of the sentence, and not specifically tying it to a single noun.

From 掛ける. That makes sense.

Done, thanks!