Propane Issue

Here is the problem. A while back I got a camper and bought a brand new tank and two-stage regulator for it. I didn't have a battery yet, but I used 120v and converter to test furnace, and the burners worked too. Now, that regulator is restricting flow and the burners light for 30 seconds, and then dwindle to near zero flow. I thought it was the regulator, so I bought another. This one doesn't restrict flow, but when I turn burners on and the furnace, it leaks propane out of the vent on the regulator at an alarming rate. The copper comes straight out of the propane box and goes to a 4-way connection which then goes to fridge, range, and furnace. I also started to notice with the furnace on it smells like propane in the camper. I sprayed all the connections I can see, and none of them are leaking. I have read as much as I can online and I am at my wits end. It might be time to take it to the RV place. Thoughts?