Go out to the link below and see if they have fittings for your grill. May not need to gut your regulator.
I had the same problem as you. I wanted to be able to use my grill free standing with a tank or cylinders as well as with the RV LP connection.
Finally found the web site for Propanegear and now have one hose for the LP tank to connect to the grill regulator. Another hose to connect the grill to the RV LP fitting using the RV LP regulator.
http://propanegear.com/
Works good for me.