I've been going through the same thing recently. The final book of my Deviants trilogy is out in January, which was my first original, not work-for-hire series. So far I'm not sure exactly what I'm going to follow it up with -- especially since the series didn't do well at all and that effects the saleability of any follow ups I do.
At the same time I've been writing a series for a packager, the third book of which I just finished. I have the fourth and final one left to write at the end of the year. Financially, this series has been a big help. Creatively, it's making me consider focusing more on MG than YA for my next original project.
So for the money side of things, I've already expressed an openness to doing more WFH with this same packager, since they pay extremely well and have fair contracts. For my future original projects I spoke to my agent about my various ideas and we settled on the three that have the most potential. What we're going to do is have me write up sample chapters and synopses for each, then shop on spec (with the openness to publish under another name, if necessary, to avoid the stigma from the failed series). That way we can hopefully get a contract before having to write the entire first book of the new series, and the money can keep flowing. I think with your track record for producing on such a quick schedule and for so many years, you can certainly do the same. I imagine many of your readers who started with CC young will have transitioned to YA by now, so your name will only be a good selling point!
So I guess just realize that you are an attractive prospect for any publisher based on your career so far -- all you need now is a solid idea. If you have that, you'll be fine!