If I had known it would be like this, I wouldn't have gotten on this ride.
この場合、次のような言い方ができますよ。
ーIf I had known it would be like this, I wouldn't have gotten on this ride.
「こうなるとわかっていたら、この乗り物に乗らなかったのに」
If I had known it would be like this, I wouldn't have XX. で「こうなるとわかっていたらXXしなかったのに」と言えます。
to get on this ride で「この乗り物に乗る」
ご参考まで!