“不定式作定语且所修饰的名词是time，place或way时，不定式后的介词一般要省去”并不是说“一定要省去”。你们书上用的which place to go to也是对的。

I had gone to Maine looking for a place to work. 我去了缅因州找工作。

Don't be above yourself. You still have a long way to go. 不要得意忘形, 你还有很长的路要走。

Get on with the work — this is no time to sit back. 好好干活，现在可不是坐着休息的时候。