Most of the time a gigantic spread like this is an automatic no play one way or the other. However having played against W&M a few times and on Mizzou a few times I can say you should lock up Mizzou -33.
It reeks of backdoor cover but Mizzou is a team that does not run down the clock and will be scoring points consistently. There is no way W&M can score on pace and their defense and transition game is not in the same realm as Mizzou.