I can agree, that many crop alternatives will work. Hemp will work for many things including bio-diesel.
One thing left off you list Road Warrior, is the by products of hemp are all useful and biodegradable, the by products of oil are useful, but plastic and cause this secondary environmental problem of not being biodegradable.
Farming for this, has it's own challenges. Hemp is a quick crop, easily three crops a year in some places.
IMO it is a solution if we use solar, geothermal and wind for home energy use, and natural gas for cars, electric commuter vehicles and such. This would reserve the need for diesel we have for heavy machinery, trucking, farm equipment and such and not outstretch our land use for growing fuel.
All in all easily done. We just have to do it and tell our "government of the people" to do as we tell them to!