It's a lot simpler to re-do the RPG, those ranges are foolish and utterly contrary to the spirit of the Novel - the real/best source.
As I said on a different page, I understand the appeal of Tanks and such ... but that's that Other Game ... it's already been done ... I'm not even above "stealing" a piece now and then but really, Tanks aren't SST.
It's pretty clear the Heinlein universe is 'different', it's not Ogre/GEV or Battletech or 40K, etc. etc.
The proposal of a Mobile Recharger is not beyond the pale, neither are some vehicles used by guys who don't qualify for PAMI - maybe the colonial sheriffs have a SWAT-carrier, whatever. Remember, Earth has been at peace for Generations, thanks to the new world order brought by the Citizens.