My pump and panel are like yours under the bathroom sink. I didn't have easy access above the gray water tank to get the vent hose down to the tank so I followed the water lines to the kitchen sink and went through where the gas lines come up. Turned back to the rear of the trailer and hooked right on the elbow. Clamped, sealed, tie wrapped and There, I fixed it.
Also added an accumulator tank to the water system and it really makes a difference. No more burp, burp, burp on slow water running. Nice.