So as the car is currently made, I can't auto fill it with fuel because after the car is full of fuel, the inserter will start sticking fuel in the storage. I have to manually fill it which could cause problems if I have 100 or so cars running all over my factory. I'll have to constantly be running around refueling. So maybe have it be electric so as long as telephone wires are in its range it continues to move.

Trunk slots can be filtered like rail wagons. Carts also send the F virtual signal at stops showing the current fuel count. Either feature can be used to create a reliable refueling stop.

That said, have been thinking about adding a higher tier electric cart requiring electric engine and battery/solar-panel equipment -- higher cost but a set-and-forget solution for those who don't like messing with fuel logistics.

A second-tier electric cart is available in v0.1.9, and works with induction charging for behaviour similar to your suggestion.