No shore power Sunset Trail RV

An ohmmeter or continuity tester will show you if there's an open in either the hot or neutral line. And yes, check for burned wires / loose connections where the power cord terminates inside the trailer.

Not a short.. if that were true the pedestal breaker would immediately trip (you hope).

Must be a break in the wire somewhere before the panel.

A short would trip the breaker at the source. I think you should be looking for an open circuit.
Do you have a transfer switch somewhere for a generator?
Do you have a compartment set up for a generator? You may have to plug another cord into an outlet to pass the power on inside the RV. Some are set up like this for a generator to avoid the cost of a transfer switch.
Do you have an inverter installed with a built in transfer switch that may be malfunctioning?

Check the connections in the panel and breaker area for burned terminals or wire nuts.

If I understand you correctly you have power at the RV entrance but it is not getting to the main breaker. First you do not have a short or the breaker at the pedestal would be tripping. If anything you have an open wire or connection.
Are you sure that you are checking for power at the input of your main breaker? Have you turned it all the way off and back on? If you have a junction box, check all of the connections they often get loose.