The two largest areas where trimming expenses is possible are the fuel for the truck, and for the driver.
For the truck, get a generator - it will pay for itself in time. Remove the [exterior] visor if you wish, but pay more attention to how you drive, too. There's a way to conserve fuel [slow and steady, use the cruise], and a way to waste it: jackrabbit starts, hurrying to red lights/stop signs, etc., not planning errands to avoid backtracking...
For the driver, get a fridge & microwave [and a rice cooker, if you want to be a real cook, lol
]. Buy at low cost places, not at the truckstops, [farmer's markets & roadside stands are often excellent]. Don't buy what you can get for free, like water & ice [refill your containers], showers on the Ohio turnpike, faxes with a coupon from Pilot's Challenge rag/mag. Get some plastic dishes you can reuse, rather than throw away - they can be 'washed' with antibacterial wipes, if you're not a fan of dishwashing.