To go would also be valid.
It's the literal translation. Whether it is a good translation is another question (and a good question).
That’s not ‘shall we go?’. That would be ‘?הוֹלְכִים’ or ‘?שֶׁנֵּלֵךְ’. This should be ‘should I go?’.
Could this be used at a restaurant when asking if it "for here or to go"?
The standart way is to say lakakhat לקחת (the question would be lashevet o lakakhat?), I would expect the employer to understand you, though
It is interesting that this would be "to take" or "to sit" instead of to go! I love seeing those little differences in language use and choice of words.