I assume your talking about low pressure (after the regulator) and not high pressure (before the regulator)
I added a low pressure line and a quick disconnect hose to my Mirada to feed a vent less heater. Sounds like something similar:
I cut the copper tubing and put in a flared "T". I installed a ball valve in the new line so I could shut off gas to the new quick connection.
I then used a LP quick disconnect and hose from a Grill smoker. These are high quality quick disconnects specifically for LP that shut the line off when they get disconnected - HOWEVER - Do not trust that internal valve, that's why I put in the ball valve to make sure LP is off to the quick disconnect line.
Here is the link to the Quick disconnect and hose I used:
Gas Quick Connect Hose / Gas Quick Connects Gas Hose Systems
Use hard draw copper and flare fittings (do not use compression fittings) , make sure its secured so it doesn't vibrate.