In the suggested translation, 'all the way' is suggested to be 'helt', but it wasn't accepted. Is this wrong, or is it just a correct answer which has not been added?
It's wrong in this instance. It could be acceptable if "all the way" was used in the meaning of "completely". But generally I think it's a unfortunate translation suggestion.
Why is this "hele vejen" instead of "den hele vej"?
"den hele vej" is not wrong, but a kind of 'poetry language' that you wouldn't hear in normal talk.
Undskyld, men hvorfor er "Det er lige ud den hel vej" et forkert svar? Tak.
Afaik, both are correct, but den hele vej sounds old fashioned and hele SMTHen is a set construct.
"Det er lige ud den helE vej" is grammatical correct, but somewhat un-natural (see my comment above).
'ahead' = frem eller fremad.
"Det er lige frem hele vejen" should also be accepted, but it wasn't.
English and Danish are closely related languages, and a word-to-word translation will often do! (with some exceptions, of course).