I put the HD sink braided stainless hoses on and the machine gun stopped. It is not the world's quiets pump, but pretty quiet under the compartment. There is no vibration noise anymore from the pex.
I also isolated my hot water heater by putting in two ball valves to completely turn off water supply to the heater and from the return line. Many campers already have this for winterizing so you do not have to run antifreeze through the water heater. Mine did not.
I did this because I dont bother heating water for a shower anymore. That waste so much propane and I estimate it is 28 feet from heater to shower head and a lot of water runs before hot makes it. I can capture the water so not to waste it, but lot of trouble…
I also saved 50 lbs by not driving around with a full water heater. Its a TC and heater is at the back where I do not want more weight.
Saving 50lbs is a big deal since that weight is 2 feet behind the truck bumper, and I tow a trailer on a hitch extension.
Next project is to run a water line straight from water heater to shower which should be about 5-6 feet distance, not 28. In winter I may heat the shower water. we'll see.