Student or Learner
1)"When I'm done reading the book, I'm going to call John and ask him if he wants to go the movies.
2)"When I finish/have finished reading the book, I'm going to call John amd ask him if he wants to go to the movies."
Would 1) be more colloquial than 2)?
Would the following sentence make sense in terms of using "being done..."?
"I was close to being done cooking food when they called and said they would like to come over."
I agree. Somehow to me "being done" sounds crude. In fact, there is a rather crude expression "I'd do him" that sounds like he got done. Avoid it.
As for the last "I was close to being done cooking food when they called and said they would like to come over." - first, "food" is redundant; what else would you cook? Either specify (spaghetti, a cake, the roast?) or leave it out. (And if you are going to be specific, you have to look at the verb too, because you don't "cook" any of those foods: you boil, bake or roast them; however, you can "cook" dinner, no matter what you are serving.)
I would say, instead, "I was almost finished cooking when..." Again, avoiding "done."