Of all the experts who have their theories of where Amelia got to, not one of them is thinking like a pilot. Amelia may have not been the best operator of a Lockheed 10 ever, but she was not stupid. She, like any of us, certainly had a "plan B". This was documented to turn back the the Gilbert Islands, 600 miles north to south, a bit hard to miss, find one with a decent sized village, ditch in the water, on the reef, in the scrub and wait for the US navy to find her.
But just suppose she had run into strong headwinds, had been hundreds of miles short of Howland and tried, after getting a fix, either at the Gilbert Islands or with sun sights, and, commercial pressures here, tried to make it back to Rabaul at best endurance speed and a reasonable tailwind. At full fuel her aircraft had a documented range of 4,000 miles and she had talked to Lindberg and also worked with P and W on extended range operations.
She could feasibly made it to New Britain or one of the offshore islands before dark. We will, of course, probably never know.