You won't need a grid everywhere to charge these vehicles. What you need is a tanker truck with an electric generator making electricity for a fleet of vehicles which is a lot less volume than a convoy of tanker trucks hauling fuel oil.
The military could also set up field solar arrays at bases that produce electricity without any grid and store in battery packs ready to charge up in remote locations. Charged battery modules can also be dropped or brought by helicopter which could not carry the weight of tons of diesel fuel.
