A low-cost alternative to all the electronics would be a dedicated (small) 12V battery to power the sound system, with an onboard charger/battery maintainer that plugs in while the truck is parked. A battery the size of the one used on my Honda Gold Wing, or even one for a lawn tractor will fit under the seat, and power a sound system without a mega-watt booster for several days without recharging.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!