The pilot reported that he departed from a private field to refuel at a nearby airport which was about 6 nautical miles away. He stated that he had selected the left fuel tank for the flight as there was only residual fuel in the right tank. During the flight, the engine began to lose power like “it was starved for fuel” and he elected to land on an area of private property. During the landing, the airplane encountered a ditch, which resulted in substantial damage to the wings and fuselage. A post-accident examination revealed that the left tank was full of fuel, the right fuel tank was empty and the fuel strainer and carburetor bowl were both devoid of fuel. Further examination revealed that during a fuel system modification, the fuel lines had been crossed and were connected to the wrong fuel selectors, which resulted in the engine drawing fuel from the right tank when the left tank was selected. When asked, the pilot stated that he completed the maintenance on the airplane and the fuel lines may have been “crossed up.” The airplane’s last annual inspection occurred in 2016. The pilot did not possess a valid medical certificate, flight review, or airframe and powerplant certificate, and had been flying, and working on the airplane which was certificated in the normal and utility category himself, without any annual inspections, since he purchased it in 2019.