General Older RV Issues

I to pull my race car with my DP which is a 1997 that has about 100,000mi on it....Had a blow out once, injector line ruptured once, radiator hose came off once, and the inverter charger has about drove me nuts. I finally bypassed it after 3 trips back to the factory service facility. I have no use for it other than to charge my house batteries and I created a way to do that with out it. My oil pressure sending unit also failed, I put all of the lights on relays after a lights out at 70mph. I think the trailer lights overload the stock light switch. But change the oil regular and I change my Alison trans fluid once a year. Leaving for Bristol next Wend over the mountains.