text: I was in my 414 with my wife. We stopped for fuel. I was about to taxi out on Runway X at ZZZ. VFR conditions. No taxiway. So before I back taxied on Runway X I announced on Unicom that I was going to back taxi on Runway X and I looked in both directions and saw no planes on final approach. I proceeded to back taxi and about 1k ft down the runway I see a plane on about a 1.5 mile final. I radioed 3 times and said I am taxiing go around. He did not answer me. I have a witness who was also in his plane with the radio on waiting for me to take off. I stopped and watched this RG continue to land so I taxied off the runway on the grass. It was soft grass and muddy so I still had my tail sticking out on the runway. I shut my plane off immediately. The RG pilot touched down, then finally saw me and did a go around. After he landed I was very upset he didn't have his radio on. Also that he didn't see us until after he touched down. He was an elderly man who in my opinion should not be flying. My plane needed a tow but a local mechanic cleaned up the wheels. I ran it up and everything was fine and proceeded with my flight back to ZZZ1.