As several people have already shown by counting, there are less than 1,200 rivets to remove. While you're removing the rivets you'll be thinking this is the worst that it can get. You're right, it gets better.
I think most people are ordering the foam kits from amazon or other sources that deliver for free. I'm told one 600 bf kit will cover the inside of a 40' bus 1/2" deep if you're careful. There are also 800 bf kits.
You won't be sorry you insulated. You'll be cussing while it's going on, but when the weather is cold you'll be glad.