The towed run home: off the high desert, across the Mojave, down to the coast

Day four is the run home, and it starts before the heat. Out of the Mesquite hotel at 6:08 in the morning, Trip A reading 7,626.8, the same odometer that closed Day 3 the night before. Trip B reset, the Ducati still strapped in the enclosed U-Haul, and the truck pointed southwest into the low desert.

The first stop is a splash, not a fill. Thirty-two towed miles down to the Moapa Supercharger, about 35 minutes on a flat, gently downhill stretch that held around 1.5 mi/kWh, and a quick 41.98 kWh for $19.73 at $0.47 per kWh, the priciest paid charge of the run. The point is not to fill the battery, it is to get ahead of the July heat and the pull into Las Vegas before switching back to the free Rivian network.

By 8:20 the rig was in Las Vegas, back on the free Rivian network with the whole towing setup, truck and enclosed trailer, parked at a charger while the Tesla Superchargers sat idle across the lot. The Mesquite to Las Vegas leg came in at 90.6 miles on 60 kWh, about 1.49 mi/kWh towing across the flat, hot desert, the ambient already up to 89 degrees. Trip A stood around 7,717. Two paid Tesla splashes and one free Rivian fill, and the enclosed box holding a steady 1.5 towing across the low desert.

From Las Vegas the road climbs to Mountain Pass and drops into California, and the Mojave crossing to Barstow ran 154.5 miles on 106 kWh, about 1.45 mi/kWh, in 93-degree heat with the motors reaching 163 degrees under the drag. That makes 245 towed miles for the day on 166 kWh.

One thing worth flagging for anyone reading these numbers as a clean trailer test, because the trip moves two levers at once. The towed legs run 55 to 65 mph in All-Purpose, while the empty baseline on the way out ran 75 to 85 in Conserve. Aerodynamic drag energy climbs with the square of speed and the power to fight it with the cube, so slowing from 80 to 60 cuts the aero part of the budget to about 56 percent of what it was. That slow, careful right foot is quietly doing a lot of the work the raw numbers credit to the trailer.

Anchor a simple drag model to the trip’s two real points, empty at 2.0 mi/kWh at 80 and towed at about 1.5 at 60, then ask what each rig would do at the same speed. The enclosed box costs roughly 40 to 45 percent of the range, not the 25 percent the fast-empty-versus-slow-towed gap implies, and tow it at 80 and the model puts it near 1.1 mi/kWh. So the honest headline is not a single number but a curve. The trailer penalty is real and large, and it gets worse the faster you go, which is exactly what a towing range calculator needs to carry.

From Barstow the road tips down toward the coast, and the last towed leg was the kindest of the whole return. Barstow to Orange County ran 174.3 miles on 108 kWh, about 1.61 mi/kWh, the descent to sea level and the cooler ocean air handing back what the desert heat and the passes had been taking. That put Trip A at 8,046.2 by early evening and the day at 419 towed miles, roughly 1.53 mi/kWh for the whole thing.

Orange County was the last charge of the trip, a Rivian stop on the coast with the trailer and the Ducati still hitched. From there it was the final push home to San Diego, through LA traffic that is its own kind of drag. The rig was parked late in the evening, roughly a hundred more miles that closed the odometer near Trip A 8,146. That last number is estimated, the arrival was the one dashboard that never got photographed, but the shape of the day is right, about 519 miles on 339 kWh.

And then it was done. The next morning the Ducati was out of the box and in the garage beside the rest of the collection, then out for a first ride around San Diego with the sun up. Some 850 towed miles home, four days and about 1,690 for the round trip, one 2025 Panigale V4 carried in an enclosed box that cost around a fifth of the range at these careful speeds and closer to half of it if you dared to hurry. The empty run out and the towed run back, the same interstate twice, exactly the comparison the trip was built to make.