The Apex ii stove has become my favorite single burner withe gas stove. It is never made anything close to this.
If it ain't broke, don't fix it, are a pretty good rule, but a brittle gas hose may be a risky project.
I have no safe way to detect if the hose inside the metal cord has begone to be brittle or not so it by my opinion it should be done regurlary, first time when you get a stove you dont trust, or every 15 years or so.
Buy some gasoline hose of suitable length and quality. The metal cord protects it, but makes it difficult to see if it has became brittle. You may make it longer than the original, but will get a more difficult start and stop sequence. When they invented this stove they made the pump unit so it will get pressurized fuel mixed with air until the temperature has raised to working temp. A longer hose make this start-up slightly harder to get working, and when you shut off, you will have more fuel in the line.
You could of course just clamp the new hose with a regular clamp, I tried, and I cut my fingers on the metal wires, and the clamp. You could do as they had made it, clamp it with a special tool. I did not have what thy had used so I cut off a little water tubing, wided it a little out in one end with this tool , but everything i n place and tried to fix it. The next best result came by using the brake line tool in picture, but the very best was using a wire lugs clamping tool like this.