Translation:I cannot arrive there before noon.
What's wrong with "I can't come down there before noon"? Where I live people say that all the time.
Why la-bas and not just la? The bas implies below? What is its significance?
It is just the difference between here (« là ») and there (« là-bas »). I would advise you not to consider the « bas » alone in this expression.
I used that and lost a heart. Am finding dl's suggestions are more like "red herring" diversions.
I thought it was "je ne peux pas arriver labeur avant midi." Would that be a valid sentence?