Saving game threads as read only files offline
If you're the GM of a game, the download function (that 'D/L') will be a button in the upper righthand corner. It's only available to GMs.
If you're not the GM, you can set a thread to 'All' and then right-click on it to save as webpage, HTML only, which will let you view it even offline. I'm fairly certain this works with threads that have been deleted from RPoL, as well, but I only have a few saved that way and no way to know if they still exist in their respective games or not at this point.