I am not going to put myself off by the continuing production of ideas, because it is not until I have filled my basket that I will be able to make a decision to commit, knowing that the writing of a first novel, or a series of novels, is a long-term project. Having gone of half-cocked -- a term derived from the faulty safety mechanisms of flintlock and other rifles that made them prone to "going off" before they were meant to go off -- has not yielded me much as a scholar except a large store of unfinished manuscripts and large library of books on many different subjects. I have to decide between old ideas that haven't died, and young ideas that haven't gone stale. And I have to take what's useful from one idea and graft it on to other ideas. For example, writing an historical (fantasy) novel about Poland and Slovakia is probably not very practical, given the distance from Beloit to the Dunajec River, and my inability to read Polish or Slovak. So doing that would require a much larger commitment than, say, writing an historical (fantasy) novel based in the Great Lakes, which are seventy miles away. The conveying of a good, like salt, from place to place happens everywhere all the time. It's a great trope, appealing to me, but we have the Ice Age Trail running through town. No need to get on an airplane or learn another language. Just a little imagination is called for, whether it's history or fantasy or whatever.
But let me sum up for myself. I'm attracted to history, but history turns out to be more or less the same as world-building and immersion. Thanks, H-G Gadamer for that insight! Combinations work very well. I like the young adult hero/ine, but my writing style might not be well-suited to YA readers. But perhaps it could be: neither Tolkien or Pullman, for instance, write down to a less literate readership, as is the case with many others. And when I was a kid, I liked best what was written with sophistication: If I want fast action and stupid dialogue I can watch movies.
Well, that's it for now, toodle loo.