There's a couple things that can cause that. One is that vibration of driving the RV along with temp fluctuations can loosen terminals. And though it would be unusual for 2 terminals to loosen enough to stop passing power, I have found found 2-3 loose terminals at a time.
Naturally, practice safe electrical testing techniques.
Since your Surge thing says the power is OK, open that box first and measure the voltage leaving that box. Tighten all terminals. If the voltage on the outputs is good, move to the next test.
Open the CB box and measure the incoming voltage. If that is good, be sure the terminals inside there are all tight.
It has to be between the surge device and the CB panel doesn't it? That's not much to test either as they usually put the input source very close to the CB panel.