The Roadtrip grill works fine off the quick-connect but you need to remove the Coleman regulator so you don't end up with two regulators in series. We run our Weber Q and ran our previous Roadtrip off the LP quick connect no problem as have many others.
I would recommend a 3/8" dia. hose instead of a 1/4" or 5/16" one and also in a 20 foot length. There are two types of jacket material, one is annoyingly stiff and hard to coil up and the other is nice and supple and easy to coil up - not sure what the industry designations are. Ours is labelled Gas-flo by Fairview who make/sell RV propane parts & accessories.
Ace Hardware has a good selection of propane fittings. The female quick connect fitting you will need at the grill end is an RV-specific part and can find it at an RV parts vendor or online. I got ours from a local industrial/commercial hose supplier.