Burlmart,
You can just replace the cord cap. Likely at Home Depot you can buy another plug and just replace the moulded one that heats up. It is likely just as said, the wires connect to the metal strips inside the moulding, and fray away with time, causing heat and sometimes fires.
There are many different types all rated for different amps, phase, voltage, etc... so be sure to read the type on your present cord cap before you head to the store, and look up the lettering on the internet to confirm that is what you have.
I found this site... http://www.ervparts.com/rv-power-cords-outlets-adapters.htm#RV%20Extension%20/%20Power%20Cords%20-%2030%20Amp
Mike