This route takes you from the northern most point of Death Valley National Park to its southern most point. No trails, no roads. It is about 160miles long and run the length of the Death Valley. The route proposed here is the one Roland Banas followed, but you are encouraged to make your own. Only the start and the end points matter. And to be off-trail. This route was first done solo, unsupported and unassisted by Louis-Philippe Loncke in 2015 in just under 8 days and done again by Roland Banas in 2018 in just under 7 days.
The route starts on Willow Creek Rd, about a 1.5 miles NE from Last Chance Canyon. Lat: 37.349741 Lon: -117.683353
The roads ends at the Harry Wade Monument at the intersection of Death Valley Road (127) and Saratoga Springs Rd. Lat: 35.632850 Lon: -116.290683
A detailed trip report is on Explorer Web: https://explorersweb.com/2019/01/07/solo-dv-crossing-report/
Louis-Philippe Loncke described the strict unsupported ethic he followed:
To qualify for an FKT unsupported and unassisted, the hiker must carry all his/her food and water supplies from the start and will leave "no trace" (carry out all the trash as well until the end). It is not allowed to receive support from anyone else (navigation, weather, carrying equipment, filming or photography, etc.). The hiker has to feel/act as he/she is the only one on the planet. No pre-placed food or water caches allowed.
All rules of the DV NP must be followed. Please ask for the latest rules. It is not allowed to camp on the Badwater Salt Flat area. It is not allowed to haul a desert cart as it would damage the fragile ecosystem.
It is fair game to use natural elements found in the park (as long as authorized in the park): resupply of water in a remaining water pool, for instance. The use of a satellite phone, distress beacon or GPS does not constitute support.
Any time of the year is allowed. The hardest would be in the full heat (mid-July) of summer. This would be the last remain challenge of DV. The first traverse in mid-summer unsupported, unassisted and off track or called cross country.