[wingnut60]

You can't have 2 regulators on the same line--too much drawdown of gas pressure.
Several have rigged the grills to bypass/remove the regulator, that is the only way I know to make use of the propane tap. You won't get into any trouble if you get rid of the reg on the grille, it is still regulated by the fiver, but would be awkward to keep removing/replacing the grille reg if you want use it away from the fiver. I think it has been mentioned elsewhere that to take the guts out of the grill reg, but that will mess it up for use later away from the trailer.
Don't know what else to do, other then tap the propane line before the main reg.
Joe