Just to align, PV is pretty close to "never" when it comes to being a game changer for long range travel. We need to see some breakthrough technology (likely unheard of) to provide the energy to meet anyone's definition of game changer.
For the record I'm a big proponent of moving toward solar roofs on vehicles, but I'm also a realist. Price notwithstanding, based on a power budget I made a few years ago, if Tesla were to put their best minds on a solar roof it would provide ~3-5% of an average US EV's annual mileage. Again price not withstanding IMHO that's an awesome way to help offset the increasing demand from EVs...but its obviously only ever going to be a small piece of the pie.
Anyway, even some desert expedition like best case for CT you'd generate something like ~5kwh/day. As a gut check, that pretty much aligns with Tesla's "15 miles/day" statement at the top of this thread. The 30-40 mi/day with solar concentrators is also a best case, desert southwest type scenario. Still in no way a game changer with respect to long distance travel, though one could imagine that enabling a fringe element to push a fixed base camp a little deeper into the wilderness.