Inconsistensies, anxieties and trauma: what's wrong with my novel?

a) Just how well does Shelley know her cousin's family? I have no clue, and it shows.
b) Why would they wait 3 days before calling her?
c) Where is her mother all this time; isn't there a family grapevine?
d) Would she really quit her course to work on a novel she doesn't even have an outline for? I don't think so...
e) Her cover story to Coral isn't convincing
f) If I was her I'd read all Jamie's diary entries in one sitting - maybe I shouldn't try to work them in logically, it's too constraining.
g) I don't think I've exposited enough, and still it's boring. How can I put more description in without making the reader fall asleep, wake up and shoot themselves rather than read any more of this tedious drivel?