In my own opinion, I'd be bored for the first half of the book. What I gathered was basically just from each ones point of view.... riding on a train? I would almost give their story once dead and on the way to hell. It isn't the same, but it reminds me (slightly) of that movie "Heart and Soul" where the bus crashes and they all get stuck following this baby around his whole life (Robert Downey Jr.) Just the crashing and dying in public transportation part, but I do like your idea. I also agree, whether or not it works depends on the writing and where you take it.
Being tried by God to be allowed into heaven is penance. I just wrote trial and whatnot as I was falling asleep/not in the write frame of mind. I see I should have rephrased. I mainly wrote the post to explain that the deadly sins are not actual sins, but things that lead to sins (I assumed they were going to write about the Catholic view on things, as the seven deadly sins are a Catholic thing). I didn't mean to imply that the OP had to write about the Catholic version of purgatory/etc, because the author obviously gets to use their imagination about such. I was stating my opinion as a Catholic, because the OP wanted feedback. Also, I was hoping that those who read my post would take it as strictly an opinion. Thanks!