"得" is kind like a sign.It doesn't have substantial meaning. You know "好" can mean "good" or "well",it means "well" as in the first sentence "我们休息得很好".愉快 can mean happy and happily as well,and it means happily in the second sentence.So for a foreigner,it's hard to tell a word means adj. or adv. sometime. Then "得" is kind of sign to show the following word is a adv. to decorate the verb before "得". So basically,if you add a "得" after a verb,you should add a adv. to show how is the action doing?

"得" here is something like an auxiliary word, typically followed by some adj. or adv. words to describe the verb word before "得". Thus, "得" is usually unneccesary to translate. Just as your example,"我们休息得很好" ('We rest very well', if translated literally). There is no word to correspond to "得". It is the same case in other examples you listed. Hope it can help you.