YOU SAID:

I would walk five hundred miles and I would walk five hundred more.

INTO JAPANESE

私は500マイル歩き、さらに500マイル歩いた。

BACK INTO ENGLISH

I walked 500 miles and another 500 miles.

INTO JAPANESE

私は500マイルと別の500マイルを歩いた。

BACK INTO ENGLISH

I walked 500 miles and another 500 miles.