True Gold is a sweet corn, Bloody Butcher is a dent corn. The F1 hybrid between them will be a dent corn, with mealy kernels. I do not expect any of the descendants to be useful as popcorn.
If you separate out the dry wrinkled kernels from this year's seed, you could recover the sweet corn trait next year. Perhaps some of them will also carry the red skin trait. Once selected, the sweet corn trait will be stable if it's not cross pollinated again.
There isn't an easy way to return to 100% dent corn. A few sweet kernels are likely to show up from now on.
My recommendation when starting landraces, if to keep like kinds together: Crossing sweet corns to sweet corns, dent corns to dent corns, and popcorn to popcorn. It's easier to not introduce unfavorable traits, than it is to eliminate them later on.
My first crossing
project was popcorn to decorative corn. It took about 5 years of intense effort to return the population to a really great popping corn. (The cross was a great decorative corn in the 2nd year, and ever after).