Looks like the Heinlein Archives are now online. You can access any of the manuscripts, look at his early drafts, the finished products, etc.
When I first saw the article, I thought they were making them freely available. But alas, you have to pay. I can’t help but wonder if the better model wouldn’t be to make all of his stories available online, and then put up google ads. I wonder how much revenue would be generated one way verses the other. Maybe the Asimov Foundation should pick the latter model, and we can revisit the topic in a few years.