Here are a couple threads that might interest you. Basically, insulin is a lot more durable than what the label says.
The first link is insulin left unrefrigerated for over a year, and also 3 years past expiration.
the-great-unrefrigerated-expired-insulin-demo
The second link is insulin left in a hot car in the summer time for 4 days.
car-baked-insulin-an-experiment-for-irish