Recreational Vehicle Lpg Tank Valve/gauge problems of the 2002 Buick Rendezvous

One day last week, I noticed that the lighting behind my gauges was out and the light on the radio is dim. Then the next day none of my windows work, they are stuck down about 2 inches. And then I get on the highway and at 60mph the front end feels like its going to fall off. And when in the drive through the engine temp was heading for the red zone, I had to shut the vehicle off. After coming to a stop and then accelerating to go, the front wheels act like they grab the car jerks then the tires squeal and car moves. I have a service engine light on now, that is some dealer code :autozone did a diagnostic check. , but the dealer wouldn't tell me what it was when I called. I have a light that came on for the brakes, as well as a light for servicing the traction system?? all this happened with in a couple days time. Its very frustrating. I don't even know where to start first, or if it just needs to go to the junk yard. Very disappointed. I'm on disability, thought I was buying a reliable gm product. Also a piece of rear window trim on the passenger side just fell off. . And $132 is ridiculous to replace a piece of trim. And I noticed on other vehicles like mine many are missing this piece of trim on the same side. Whats up with that?.