I will stick solely to the OP's question...
It makes sense to install a propane shutoff cock valve near the junction of the feed line to the heater. I am very, very touchy about what kind of supply line I use for the heater. Routing the line so it doesn't get in the way is one of my primary objectives. I have had to have custom LPG hoses made up with crimp 90 degree elbow fittings at a hose place in order to make a clean and neat installation.
Best of fortune with your installation. You're going to love it! The pot bellied stove effect on a cold day is priceless!