What Do I Need??? Help!!!! ;-)

If you have a grill like the one below, then the bottle already screws into a regulator - and all that you need is the extension hose that mates to the quick disconnect and is threaded on the other end the same as a 1 quart bottle. My Stay-A-While Deluxe comes with a gas grill hose that screws directly onto my Coleman portable grill's regulator. Not knowing the quick-disconnect that you have, I would be inclined to drive the trailer with your grill over to a CW or RV store, walk a salesperson out to the trailer and say "I need a propane hose to go from this quick-disconnect to this grill". I would then test the hose on the grill (by lighting the grill) before leaving the store.

If you click on this link and then click on the "Standards/Options" tab, in the right-hand column it shows the "Coleman Outside Stove/Grill w/Griddle" as optional.
http://coleman-rv.com/floorplans/Expedition