I’ve got good news and bad news for those who have dreamed about towing a full-function travel-trailer with the Model X. First the good news: It’s possible. The Bowlus Road Chief pulls it off with a efficient combination involving ultra light-weight design, low height (6’4” interior headroom) and a compact aerodynamic shape. Now the bad news: it costs as much as a fully loaded Model X, and you will may have to wait almost 18 months to get one. Still, for those who appreciate good engineering, the Bowlus is as unique to the world of travel trailers as Tesla is to the world of automobiles. Its monocoque (stressed skin) structure, like most jets uses aircraft-grade aluminum and thousands of rivets to achieve high strength with low weight. The obsession with efficiency and weight savings extends to the living quarters too,which depending on your perspective has the feel of either a small luxury yacht or a large corporate jet. Checking in at less than 2500 lbs, the low weight of the Bowlus Road Chief has multiple advantages for the Model X. With a tongue weight of less than 200 lbs, it can be towed with the 22” performance tires set at 50 psi. Disconnecting the trailer at Supercharger stations without pull-through slots is fast and easy. If you’re in a hurry it only takes 90 seconds and in flat locations the trailer can be pulled by hand into a nearby parking space (the trailer’s brakes can be engaged and powered by its own 12V system). The Road Chief can be towed up most mountain passes (expect to consume 12-13 additional miles per 1000’ elevation gain, versus 8 additional miles for Model X when it’s not towing anything), and the trailer’s weight can be fully regened on downhill grades of less than 7% if the pack is warm (expect to recover 11 miles per 1000’ decline, versus 7 miles for Model X itself). Last but not least, in Ludicrous mode you can zip from 0-60 in about 5.5 seconds with the Road Chief, making lane changes less challenging relative to other towing situations. While low weight should make it possible to get over Donner Pass (charge to at least 95% at the Rocklin Supercharger), it’s only part of the battle when it comes to driving range. The dominate factor is aerodynamic drag. Because the Model X is heavily optimized with a Cd of less than 0.25, its range takes a significant hit when you tow anything that extends outside of its slipstream, especially if the item being towed has a poor drag coefficient. The Bowlus is a winner in this respect. Because it is narrower than Model X, less than eight feet tall,and relatively aerodynamic itself,the range hit is tolerable.By that I mean the Bowlus makes it possible to get around,not necessarily easy. Unless you are traveling less than 100 miles without much elevation gain, you’ll probably want to stay below 55 mph in order to benefit from the fact that aerodynamic drag goes up by the square of vehicle speed. Dropping from 55 mph to 50 mph, if you can stand it, will improve range by about 10%. How far can you go? Towing the Bowlus on highway 101 near Oxnard, on a relatively flat course with light wind and 60 degree temperatures, the steady-state power draw at 55 mph was about 540 Wh/mi. At 50 mph it dropped to about 485 Wh/mi. Model X has an EPA range of about 250 miles, which translates to about 340 Wh/mi. So, under ideal conditions (summer driving, no significant headwind) it should be possible to go 175 miles if you limit your speed to 50 mph. Fortunately, most Superchargers are spaced less than 125 miles apart, which means 55 mph should work okay even with a light headwind. Driving in the northwest a few months ago, it was not unusual to see Model X drawing 500 Wh/mi due to the combined effects of AWD with torque-sleep disabled and the heater running in 25-degree temperatures. But even then I didn’t find it that hard to get around; it just took a lot of extra time at each Supercharging stop. This brings up another advantage of the Bowlus Road Chief. Because of its airtight design and high-efficiency heating and air-conditioning system, it only needs the 120V 30A power connection at the RV park hookup, which leaves the 14-50 available to charge the Model X. You’ll want to limit the car’s charge current to 28A to avoid flipped breakers, but even at that rate (about 18 range-miles per hour) you’ll still get a full charge overnight. For camping where there are no hookups, the Bowlus can run on its high-efficiency 12V power system, which among other things powers its LED lights, a small high-efficiency refrigerator, and the water pump. There is an exterior 12V connector that can be used with a portable solar panel the charge the trailer’s 12V battery. While it hasn’t been tried yet, I’m guessing it will be pretty easy to make an adapter cable allowing the Model X’s always-on 12V accessory port to charge the the trailer’s 12V battery during cloudy/rainy days or in heavily shaded areas. There are other thoughtful engineering choices that Tesla owners will appreciate. The trailer has been designed with an 80-year service life goal, meaning that everything is accessible and replaceable, right down to the foam insulation in the walls. Convection-based ceiling vents reduce the need for A/C use. A reverse pressure ventilation system for the toilet eliminates the bathroom smell that is common with most RVs. The tanks are located inside the living space to avoid freezing during winter camping. The black-water tank is a compact hand-carry unit (like some European trailers) that can be emptied in public restrooms, eliminating the need for dump-station stops. The bottom of the trailer is a flat sheet of aluminum, and the monocoque design keeps the center of gravity very low. Driving 55 mph with the Bowlus in tow, you can almost forget that it’s there.You don’t see it in the outside mirrors, and it corners effortlessly just like the Model X. The trailer weight is less than half that of the vehicle, so acceleration and regen characteristics are not radically altered. You hear the usual ball-hitch clunking noises when accelerating and decelerating, but it isn’t as loud compared with other trailer-towing scenarios. Finally, a few thoughts on ordering a Bowlus Road Chief (which I’ve already done). The relatively long wait (currently just shy of 18 months) and the non-refundable deposit ($10k) are nothing to smile about, but they’re not all bad either. By the time Tesla owners start taking delivery, the Supercharger density may be twice what it is now, and a larger battery pack may be available for Model X. Both would make it easier to get around compared with today. I suspect the resale value for the Road Chief will remain high, because it’s built to last with high quality materials, and because any used Bowlus that’s available right away is probably worth almost as much as a new one you have to wait for. As for insurance, it doesn’t appear to be much of an issue. Liability goes with the tow vehicle, so insuring a trailer for theft/damage doesn’t cost much, even when the trailer value is high. State Farm told me the Bowlus would probably run about $500/year.