Keep going straight down this street and you'll get there.
Just keep going to the end of the street
1) if you keep going straight down this street, you'll be get there.
この道をまっすぐ行けば着く
This street = この道
If you keep going straight = まっすぐ行けば
You'll get there = 着く[you'll arrive]は同じ意味ですけどyou'll get thereはカジュアル言い方です
2) Just keep going to the end of the street
ただ道の端にまっすぐ行ってだけだよ
この英文はよく使いますよ
We just have to keep going straight down this street.
We just have to keep going straight down this street.
の直訳は、「この道をまっすぐ進み続ければ良いだけだ」の意味です。
downはalongなどに変えても大丈夫です。
just have to Vは、「Vしさえすればよいだけだ」の意味です。
説明文に「友達とどこかに歩いて行っている状況で」とありましたので、主語をweにしました(*^_^*)