STOP.
A standard 30 amp RV outlet has ONE hot, one neutral and one ground.
A standard 50 amp RV outlet has TWO hots, one neutral and one ground.
So if doing a STANDARD repeat STANDARD 30 amp outlet, see above.
But if you are pulling 4 wires and have two 30 amp breakers (opposite sides of box so 240 between them) on your house breaker box, there is a reasonable option: Wire as a 50 above, but now instead of 100 amps @120 VAC, you now would only be able to draw 60 amps @ 120 VAC. But much better than just the 30 amps @ 120 VAC a regular 30 would give you.
The secret is that you pull 4, not just three wires.