Propane service for Tear

I have seen most RV's and Tears with propane tanks on the tongue of the trailer. Are most of those plumbed to the appliances (have gas lines running through the trailer)? Or do people just move the tank to the appliance when they camp?
I am thinking I will just move the tank to the grill when I need it, but wanted to confirm that is the norm.
I am thinking I will just move the tank to the grill when I need it, but wanted to confirm that is the norm.