Well, today I did it ... turned an existing eBook into a paperback version and released a new book in both formats. In the end, despite a lot of time fixing gremlins, they were gremlins of my own making and now that I understand the process, it's relatively easy. Formatting a Word Doc into a paperback-friendly shape is just that -- an exercise in page setup and margins. Creating a cover design was also quite straightforward when you're not intimidated by the technicalities. It's simply two 6X9 panels separated by a spine that's determined by a "page-counter X paper choice formula" and just make sure you don't go near the edges with text or important illustrations.
KDP has all you need to know on its website, and in the effort to be exact in the information it can be unnecessarily overwhelming -- at least when you're only talking text-only novels.
One piece of advice I can offer, stick to one computer and one instance of Word. I was swapping between several (don't ask) and the formatting, styles, etc, didn't translate well between the different installations of Word. And whatever you do, don't trust everything has worked. Physically scroll through your MS to check for missed Page Breaks and stuff (annoying, but worthwhile). Also, the end result is printed pages, so when you convert to PDF open the Options Panel and turn all the stuff related to making a PDF searchable, Bookmarks, Chapters, and so on. Optimise, but otherwise keep it simple and basic.
Pricing was interesting. At the end, the process tells you how much the printing will cost, but when you actually go to the pricing dialogue the minimum price is almost twice that (shipping, etc, I suppose). I decided to price the book(s) so that I got roughly the same royalty payment I get from the eBook ... so an eBook for $5.95 is a paperback for $14.95. But I see the paperback as an added extra, or a convenience, if you like, for readers who demand print and I see no reason to cut the price to no profit for me just to make it look attractive ... and I'm not making a million bucks on the price either.
Bottom line -- once you know and understand the process, as others have said, it's no big deal. Worst chore is the endless scrolling through your MS to check it, and then if you DO fix anything, it likely changes the TOC page numbers which are a manual input and you have to redo them all again. Do your TOC absolutely last.
Now I'll sit back and wait for the enormous sales.