He was so adventurous he kept walking ahead of me until I couldn't see him any longer.
He was so full of energy he couldn't wait for me and eventually I lost sight of him in the distance.
ーMy boyfriend and I went hiking, but he was so adventurous he kept walking ahead of me until I couldn't see him any longer.
「彼氏とハイキングに行きましたが、彼はとても冒険好きで、私の前を見えなくなるまでどんどん歩いて行きました」
to go hiking で「ハイキングに行く」
adventurous で「冒険好きな」
he kept walking ahead of me until I couldn't see him any longer で「どんどん歩いて行って見えなくなった」ことを表現できます。
ーHe was so full of energy he couldn't wait for me and eventually I lost sight of him in the distance.
「彼は張り切っていて、私のことが待てず、最終的に遠くに彼を見失った」
to be full of energy で「張り切る・やる気満々である」
eventually で「最終的に・ついに・そのうち」
to lose sight で「見失う」
in the distance で「遠くに」
ご参考まで！
カナダ 
