Yeah, I was trying to find a post I did a while back that gave more specific details about geography, distances and dates, alas I did not find it.

-Kronatron

 

The distance between ships is never specified nor is the distance of the Ark. We see a map of both ships in Equal Measures, but are never given a distance. Being prehistoric Earth, the continents wouldn't be where they are today so it's plausible to think that they traveled a thousand miles from Africa to Oregon. Optimus must have known it would be quite far since he had Rhinox ride along on his board. Poor Dinobot isn't quite as important as the space-time continuum, even if he did sacrifice himself to keep it on track.