I just need some clarification as to how the stepladder special object works. Does it make a ladder between the square it occupies and every square of higher elevation adjacent to it? even on the diagonal? Also, the way its worded requires that the two squares be adjacent, which they are not because they are at different elevations.

Oh and whilst looking up elevated terrain I came upon this entry in the rulebook and was wondering what situation it might be referring to:
A character at a lower elevation is adjacent to elevated
terrain when the only reason the square in question
is not adjacent is because it is a higher elevation.

Actually, the Player's Guide clarifies the text to read:

You can still be adjacent to the actual higher elevated square, it's just any characters/objects occupying said squares aren't, generally, considered adjacent. As for whether you can go up the ladder if on the diagonal, I don't see why not. Two squares on a diagonal are considered adjacent and the stepladder doesn't say anything about treating it as if it was a printed ladder.