The only road access is a tortuous mountain route.

唯一的陆路通道是一条蜿蜒的山道。

...these long and tortuous negotiations aimed at ending the conflict.

旨在结束冲突的漫长而曲折的谈判

The parties must now go through the tortuous process of picking their candidates.

各政党现在必须进行挑选各自候选人这一迂回复杂的程序。