If you are going to till, there can be no slope in the ground. All of my new plots were designed with two things in mind: the best soil and the flattest ground. Deer travel patterns be damned. Deer will shift their movements to access a great plot.
For years I've been reading about how certain plants - especially turnips/radishes - will "break up" hard ground with their deep tap roots. Whoever came up with that idea has obviously never worked with REALLY thin, hard soils, because in real-world tests, it doesn't work. The plants just produce tap roots that run sideways just under the soil's surface, and the turnips grow up out of the ground, with just their root tip making contact with the soil.
The one technique I do agree with for building soil is the spray/broadcast/ mow planting technique. Do that for 4 or 5 years and all that mown material eventually breaks down and turns into some nice humus a few inches thick.