I took a 20lb tank I had from a old grill I was throwing away and bought a hose that connects straight from it to the weber without any modifications. Seems like the hose was Weber branded for about $30 and the tank was free since it was no longer being used. Even if you had to buy a new one for $50 full, your way ahead of doing all the modifications and can switch between a lantern, stove or any other item that uses the "green" bottles.
I'm also not tethered a certain distance from the camper or the tanks on the front of the camper. If I want to setup the grill over on the picnic table, I can do so without having a hose run across the ground for people to trip over.
Just my solution, thought I would share.