Unless your game states have combinatoral exlosion, would it not be better to generate all of that pre-build? If templated you can generate a few hundreds of thousands of templates to use for any circumstance, then instantiate and stitch together those templates during the game runtime.
I dunno, for game prose I expect that a tiny highly quantized model would be sufficient (generating no more than a paragraph), so 300MB - 500MB maybe? Running on CPU not GPU is feasible too, I think.