InDesign does not seem as complicated as I had feared it would be, but it certainly has its quirks and I think it will take some experience.
I've made the cover for Hapax in Photoshop thanks to Walter Savage's art. I'm quite happy with how it looks. I'll, of course, be publishing an unaltered version within the magazine.
Now I just need to dive in, tackle KDP and publish on the web!