Fast food abounds in Blythe, so it's tough to recommend stopping there. I'm sure there are local gems to be found there, but I don't know where they are. We generally pack sandwiches and water, and stop only for gas until we hit Phoenix.
Although some time has passed, I once worked for 21 days in Blythe. The best grub in town was Popeye's. After a few weeks in civilization I had to return for 18 more days in Culinary Hell. I hope to never return!