Oh boy. I'd hold back some rye and spread it really late (like after october 15th) when the sun isn't so powerful, and hope for some late fall moisture to get it to germinate, including first snow. I'd keep throwing low cost/high biomass crops in there and hope you hook a rain eventually. I'm talking japanese millet, rye, flax, barley (if in spring), yellow sweet clover (fall), white sweet clover (spring), chicory, plantain, and even get some rag weed and try it. I'd go harvest some thistle seed and throw it out there. Anything green will help until you can make a blanket over that sand. I'd even bless the idea of using hairy vetch to get something growing out there.