From what I've read, there are a few RV grills that work directly from the 11" aux. connector. You might want to check out your grill and see if it's one of them. Otherwise you have to get rid of the grill reg. and hope that it's designed for 11" orifice pressure. There are some that aren't, like my Olympian grill, which requires 15" for high-fire. I had to tap between the 1st and 2nd stages of the tank changeover/reg. where I got 18 psi and that was perfect for my grill with it's regulator intact. Then you need some sort of manual needle valve to replace the RV grill reg/control for burner control otherwise you'll have nothing but high-fire.
Sooo, I'm also curious how guys handle that conversion. It might be a lot less brain damage to just buy a grill that operates on 11" w.c. supply pressure.
The only other option I can think of is to buy one of those Rube Goldgerg extend-a-hose kits so you'll have tank psi to the RV grill reg/control. Craig