If you are replacing the gas line you will most likely replace it with soft copper. If so you will need a flaring tool to make the flares on the pipe. Depending on how many things will be on the gas line. If you are supplying a heater, ref., and stove you should run a 1/2 in. line from the hose coming off the regulator and branch off with 3/8 in. to each item.
You can buy the copper and tool at any Big Box store or plumbing supply dealer.
I would check with a propane supply house for the regulator for reasons of cost. If not there any RV dealer will have it.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles