Copper tubing with a flare nut would go on the fitting in that picture. Inside the camper all the gas lines are copper tubing.
If the stove is the only gas appliance you could just run a copper line along the wall under cabinets and couches and such to the front.
Typically the gas stuff such as fridge
, stove, furnace
, water heater are on one side so that a single line can feed them all with a "T" fitting to continue the main line and provide the branch off for each appliance.
I'm always torn when people ask about doing gas lines, I learned how to properly flare, bend, and cut copper tubing. It really is not that hard, someone explained it to me, I tried it on some scrap, messed up a few times, cut that off and tried again BUT having someone blow up their camper trying to learn from an online explanation has... shall we say some down side?
Best bet is maybe to hire someone to install the stove gas line, any plumber should be able to run the copper line, take it to the shop and watch how it is done. Ask questions, most skilled trades (but not all) like to explain their work. So ask up front if this is OK.
One end has a fitting out by the tongue that attaches to the rubber line coming from the tank regulator. One end has a T fitting with one side of it going up to the stove the other capped until you need to extend the line. Watch what they do and how. Then how they test. ESPECIALLY how they test.
If you decide later to add a refrigerator
or some other propane appliance then either go pick up the tools (inexpensive) and try it for yourself on some scrap tubing, if you feel comfortable with doing the work to add a line do it or take it back to the plumber.
Unless you are sure of your ability to test your work, and committed to re-test at least a few times to make sure it does not shake loose Don't attempt gas lines.