Rear LP connector-hose?

This is a great way to go. It's a ready made kit and comes with everything you need. I just converted my WeberQ with their Converta-Q kit and am in love.

http://torjik.com/#_convertac

I converted my grill and my portable oven to hook up to the regulated gas outlet on my trailer. Be aware that the gas is already regulated. Putting another regulator in series will cause your grill to not stay lit. Also be aware that the proper brass fittings for gas use are pricey. But for the years of use you'll get from them, they are safe and a good value. I bought the hoses and quick-connects on Amazon, and the other fittings from my local hardware store.

One problem I had was that my coleman stove was high pressure, so it will not work. My Weber Q works awesome.

I found my connectors on Amazon.

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.