Adding a 30 A connection to my 50 A 2014 Cougar

Hard to believe you would be having trouble with a 50 amp service simply by using a 1500 watt heater. Are you tripping the park 50 amp breaker? Or are you tripping one of your inside breakers?
As mentioned, the 50 amp service is actually two legs of 50 amps each giving a total of 100 amps.
If you are tripping an internal breaker, then you may be loading that one breaker too much. Likely multiple outlets and/or other devices are connected to each breaker in your panel. Try the heater in different outlets and see if you still have a problem.

We can run two ACs, the microwave, water heater on electric, and the clothes dryer on 50 amps with no problem. And when it is cold we can run a heater, the electric fireplace, the same microwave/water heater/dryer and still have no problem.

What is your trouble exactly with your high draw items? I have a 50amp rig also and have no issues.

Some pedestals can handle and some cannot. I wouldn't count on being able to do it.

In case you don't know, that 50a connection actually gives you potentially 100 amps of power. Maybe you just need to plug the heater into a different leg. You might have too many appliances on one leg and nothing on the other. I would be checking my wiring closely before doing that mod that may not be of any benefit.