Portable solar isn't going to cut it. Consider if you use 180 kW-hr to go 400 miles then a 200 watt solar panel will take 900 hours of ideal sunlight to collect the energy. Current state of the art PV panels produce about 18 watts per square foot. Over a whole day a panel probably makes about half its rated output and at night its zero. So it'll probably be quite a lot of time using a little solar panel.
So drag along a 2 kW generator, which will still take 90 hours to return 180 kW.
Those Telsa Supercharger stations can deliver 72 kW, which costs about $0.22 per kW-hr. So a 400 mile trip that used 180 kW-hr costs $39.60 (that's probably equal to doing it in a car). To get a handle on that, if you have a single phase 240 V, 200 amp service to your home it can in total summing all the circuits deliver 48 kW. It would take you and your neighbor's full service running 100% for an hour to charge after a 400 mile trip. It would take I think two 50 A / 240 V circuits overnight to charge the 180 kW-hr battery.
For comparison a gallon of gasoline delivers about 33.5 kW-hr equivalent, which means a Telsa station works out to about $7.37 per gallon equivalent and a 5 gallon jerry can carries 167.5 kW-hr.
You see the clear increase in efficiency of the EV itself since there's so much lost to heat in internal combustion. That inefficiency, BTW, is just shifted to the power plants though...
Which also means you'll need to bring along something like 20 gallons to run the 2 kW generator you'd use to get back from the Dollhouse by next week due to the inefficiency of its gas engine.
Like I say, just generating the power directly using a hybrid engine and collecting regenerated braking power, solar, etc. to increase overall vehicle efficiency makes sense. A pure EV only is practical if you're never far from a grid-tied charging station.
