1)To heave something means to lift something really heavy and try to move it around. In this sentence I imagine a very heavy person trying to lift themselves off the ground or a couch or something. We usually say something like this as a personal degradation as in, "I am so fat I have to heave myself off the couch to do anything."
2) To ration something means to limit how much you use. In this case, the person has no hurry to finish the book, so they will ration how many pages they read in a day.
3) To be WRY, is to have a bit of sarcasm to your tone of voice. Kind of like telling a really funny joke, but keeping a straight face and not laughing yourself while you tell the joke. Also, to keep a straight face while making fun of someone or something. For example, many comedians can make fun of politics and politicians without laughing themselves.
To be WITTY is to be able to say smart and/or funny things really quickly in response to something. People who are witty are quick to respond to a topic in a smart and sometimes humorous way. Many comedians are known for being both WRY and WITTY.
4) You are correct about this meaning of "transpire"
5) "High game" refers to a wild animal (game) that has been dead for awhile and has started to decay and smells horrible. So if someone smells like high game, you can imagine it must smell pretty bad.
Hope this helps.