YOU SAID:

I rode the horse right into the lake.

INTO JAPANESE

私は馬に乗って湖に入った。

BACK INTO ENGLISH

I went into the Lake on horseback.

INTO JAPANESE

馬に乗って湖に行きました。

BACK INTO ENGLISH

Riding on a horse and went to the Lake.

INTO JAPANESE

馬に乗って、湖に行きました。

BACK INTO ENGLISH

Riding on a horse and went to the Lake.