In 1959 Max Conrad flew Comanche 250 N110LF non-stop from Casablanca, Morocco to Los Angeles, a distance of 7,668 mi (12,340 km).[5] This distance record (for aircraft in the 1750-3000 kilogram weight class) stood until 1987. With interior seats replaced by fuel tanks, the aircraft was loaded 2,000 lb (910 kg) over its production gross weight limit when Conrad took off from Casablanca.
A few months later, on November 24, 1959, Conrad set the record (that still stands) for the 1000-1750 kg weight class, flying from Casablanca to El Paso, Texas in the same aircraft fitted with a smaller engine, with a flight time of 56 hours.[
Got beaten to it. The single Comanche is pretty hard aircraft to beat for payload and range. The twin isn't too bad from what I hear as well.