Yeah, the complexity and cost is pretty high at that sort of of localized power density. Most truck stops max out on nighttime parking (about 100 spaces), and assuming all of them charging at the time, a moderately sized truck stop would require about 20MW peak power...even more if they plan on having megachargers. The biggest problem is line capacity...you won't be able to piggyback on local infrastructure. You'll have to run dedicated lines from tens, if not hundreds of miles away from the nearest distribution station. Remember, most truck stops are far away from population centers, and thus electrical infrastructure, as a matter of practicality. They need too much land.

I'm not betting on hydrogen specifically because 1) it's too complex, and 2) while the volumetric density is within the realm of feasibility, it's still not great. But I am betting on fuel cells. Solid Oxide Fuel Cells in particular. They're already extremely efficient, and also produce high grade (i.e. easily recapturable and convertible) heat. And they can use hydrogen, but they can also use methane, ammonia, butane, propane, diesel, gasoline, or any other form of fuel (I've run one off of wood chips!). And that flexibility has a lot of power, especially with the future of abundant and cheap non-peak power costs and rapidly developing synthetic fuel technologies.