Q If I buy one of the new iPads, is there a straightforward way to transfer the contents, including Kindle books, from my old iPad??
A iTunes will register a new iPad as a separate device, and you will need to set it up, complete with all the apps, tracks, books, and more, when you sync it with your Mac.
That is the best way in any case, although unfortunately you will need to register the Kindle app with Amazon and download those titles which you want on the iPad. This will enable you to leave old and unwanted content and apps from the new device, freeing you up some storage space for the new products which you are bound to download to it.
Content stored or shared in iCloud will also become available as soon as you have set it up with your Apple ID.
Updated from the original, which was first published in MacUser volume 30 issue 12, 2014.