I never liked the grill that came with our camper.
For years we used a Thermos version of the Coleman Roadtrip grill which served us well (although not as good as the Roadtrip).
Then I finally bit the bullet and bought a Weber Q 100 small grill, and use a 20lb propane tank. I can certainly use the small green tanks with it, but the big tank pretty much assures that I won't run out of propane during the weekend.
I looked into using the campers propane system for the grill, but went with a separate tank. Big advantage of using a separate tank is that you can setup the grill anywhere, without having to be tied into the camper.