Thor to the rescue!

...using just 8 gm of thorium in a car should mean it would never need refueling.

Well, that's the kiss of death, isn't it.

...developing a portable and usable turbine and generator is proving to be a tougher task than the laser-thorium unit.

Did you get that? Nuclear power is the easy part! Makes me wonder if mating it with a Stirling engine might be the way to go?