By the time you retrofit the truck, the stand alone generator is probably going to be cheaper to start with.
You are burning a lot more fuel than an equivalent generator.
You are putting more wear and tear on a device that costs tens of thousands of dollars to try and save a small number of dollars.
It's one of those things that sounds great until you dig into the details. I'm talking about using the truck as a stand alone generator. Beefing up the cables so more amps go to the house battery bank while driving can be a reasonable option but you likely aren't getting 300 amps to the battery bank and that would likely overload the battery bank anyway.