John: When will you come back home from work?
Carter: By 3 PM at the earliest and by 5 PM at the latest. It won't take me later than 5 PM to reach home.
John: [STRIKE]When[/STRIKE] What time will you [STRIKE]come back[/STRIKE] get home from work?
Carter: [STRIKE]By 3 PM at the earliest and by 5 PM at the latest. It won't take me later than 5 PM to reach home.[/STRIKE] Between 3pm and 5pm.
You can say It won't take me longer than an hour, for example. "It won't take me" does not work with "later". Tdol's suggestion in post #6 is good. In conversational American English you might say I'll be home by five at the latest.