If the Longmont, CO restaurant asked me to refresh their brand (which they didn't), this is what I would present to them. An updated turtle logo ("Tortuga" in Spanish), a new slogan that encompasses their varied culinary influences, upscale but approachable typefaces, and bright, coastal colors.
Tortugas also offers their own hot sauce, called "Pete's Heat." Here is my version in the style and color palette I used in their rebrand.