You might want to consider a Stay a While or Extend a Stay Tee. They are available with a outlet and hose for an external grill and an outlet and hose that will fit an external cylinder. The later can be handy when you are stopped for a while and don't want to move the motor home to fill up the on-board tank.
They have some built in safety devices so are better than just a plumbing Tee.
You can get a longer hose for the grill. As I recall the one that comes with it is about six feet long. A friend had one made that was about 20 feet long.
I installed mine myself - took maybe ten minutes.