Ever try flying from the US mainland to hawaii in a B-17 using only a compass for navigation and hoping that after 14 hours, you weren't a few degrees off, missing the island completely?
Never did that, but I took the DC3 from the Galapagos to Christmas Island (SEOE-PLCH) using compass and clock only... over 3900 nm... naturally, i missed the island by about 100 miles (wasn't peeking at wind direction using shif+z, either, so I drifted)... also ran out of fuel despite having modified the model so it could carry 2800 gals. of fuel (didn't figure on headwinds so heavy).
There is an autopilot, but it's only slaved to the mag. compass. I did hit "D" every coupla hours, but that just simulated having what any RL pilot would have: time estimates on crossing magnetic variation 'lines'.
If I'd had a way to take star fixes, i might've done better... very tough to fly that far over water with absolutely no way to get a fix for latitude...
I think California-to-Hawaii would be a snap in the B17; (big target compared to Christmas Island!)
...got to try that sometime.