I've driven part of his route and can confirm that his results are more than possible.
By the way, if it helps I've got results that are at least close in my Elantra, though my car isn't quite as efficient as that Saturn:
This is just my challenge log, but it took so long to complete (1111.9mi on 17g -- right at starvation) I don't have any other tanks in it. You can see my progression in the following:
Both graphics are clickable...
Heavy use of P&G, FAS, and bump start are a formidable combination. Since purchasing my Insight I've only continued to improve my application of these techniques in both vehicles.