One plan is to let it go reproductive (seed pods on the bottom 1/3 of the plant), then roller crimp it & plant green. The rye will be a goner by then, and the vetch should mostly die if it's mature enough, and a post pass with glyphosate will take care of crimson clover (easier to kill than red clover).

As you know, killing a thick stand a couple weeks ahead of planting comes with its own risks too...this past spring it started raining right after I killed some trit + crimson clover....and corn never got planted; ended up being late-planted beans.