Yes! You can run a full node including Lightning on a van. I know of a successful case. There are three requirements: good amounts of energy which means all the solar panels you can fit on the roof, a lifepo4 battery, and good unlimited 4g/5G connection or even Starlink (but this requires more energy, even on the mini version). Use a mini PC with the lowest energy comsumption possible and a good 2Tb SSD. The one that Umbrel sells consumes only 10-20W.