I hate to say this but "time and time again, people shotgun (i.e. replace) a perfectly good working component. So many people on the forums site are guilty of this and do it, without properly finding out the root cause failure mode (i.e. problem). As you can see, you went through the time and money replacing a good working heating element without analyzing what the real problem it.
I am not sure what model you have, but you can find it on the web.
It looks like the heating element is controlled via a relay which is triggered by a thermostat. If you wanted to go only electric, you must run the relay through the thermostat. The thermostat only will not handle the current, thus the relay is required. If you do not have any electrical knowledge, then maybe someone in the campground where you are may be able to lend a hand. They must be able to read the schematic and cut/connect the correct wires. Doing it yourself without the proper knowledge and equipment (i.e. voltmeter) will end up more problems and money.