Anode rods should deteriorate as they pull stuff out of the water that would otherwise bond to the metal lining of your tank. The rods are often removed when a camper is winterized to allow the water in the tank to drain as much as possible. There is a valve on the inside of your camper at the back of your water heater that must be turned in the direction the water will flow into the tank to get water in the hot water tank. It is there because if antifreeze was used, it isn't great to fill the hot water tank with it.
Typically you will have a Suburban water heater from that era. There is a label on the outside of the unit when you have that water heater door down. The actual model will tell you how the water heater heats. It will surely have a switch on your inside idiot light panel where the tank levels lights are. When you turn this on AFTER filling the tank (replace anode and set the bypass valve as explained), you can check the tank fill by opening the pressure relief valve on the outside a bit. Water will come out if the tank has water in it. Then you go back in after making sure your propane is on (light the stove to be sure) and push the rocker that says water (or something similar). A red light will come on indicating it is trying to light and will go out when the pilot light is lit. You will then need to open a drain to get water circulating through the hot water tubing. It usually takes awhile for the water to get hot.
On many Suburban hot water heaters of that era, there is a black toggle switch on the outside that also heats the water with 120VAC heating element. Make sure your breaking in your power center for the water heater is on as many use this to turn off electricity to the hot water heater rather than mess with the toggle on the outside. Higher end water heaters have that toggle on the idiot light panel. You should never turn on the electrical parts of the water heater without water in the tank as they burn up fairly easily if dry.
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