I finally know now what's been hindering my creativity and will be testing the theory. (Hint: middle age sucks, but balance can be achieved.)
A major burst of creativity today after a small test of my theory (food-based) had me writing a great chapter on #7 and planning a possible second series of Forgotten Worlds, if I want to continue beyond the initial 20-30 books. I had considered it but not nearly as fully as it came today. it would be a season two with its own big climax, even bigger than the first "season".
Or I could just be done after the first, depending on the exact ending I ultimately choose. The climax of this initial series will be exciting and final. However, I can continue if I want. All it requires is leaving one key question unanswered.
We'll see how this first season goes. #7 was a bugger to get going, but I've added a lot in the last couple of days. I seem to have found my footing with it now. I still can't wait to write #8, but now I know what this transition between #6 and #8 is.
By the time I'm done with all of the Forgotten Worlds, the series will be something extraordinary. If I feel like extending it, I do have that option to make it even bigger than I originally intended. And I thought this first one was exciting enough!