(Thor I#462)- In modern years, Charon delivered the war-god Ares to Pluto, who wanted his allegiance in using Thor's brief madness as a weakness to attack him.

(Thor Annual#19)- Charon transported Pluto through Tartarus while Pluto examined various people he had imprisoned there while scheming a new attack on Thor.

(Hercules III#5) - Charon ferreyed Hercules, television producer Gordon Allsworth, Jimmy the cameraman, and Robert the assistant across the River Styx. When Robert told him that he loved him on "Tales From the Crypt," Charon broke his thousands of years of silence to curse Robert out and throttle him.

Comments: Adapted by Stan Lee (?)
Reused in Marvel Comics by Ron Marz, Jim Starlin and Bruce Zick.

In Etruscan Myth, Charon is called the son of Mantus (Hades) and Mania (either Persephone or Hecate). This is obviously erroneous.
    --Obvious to whom?

The ocean goddess Eurynome is also mother of the three Charities (Roman Graces) known as Pasithea (wife of Hypnos), Euphrosyne and Aglaea (Roman Charis, second wife of Hephaestus) by Zeus. If the account of Eurynome as Charon’s grandmother were true, the Charities would be his aunts.

The twist in the end assures that the story was not a dream. The Red Skull in this story was not identified. Follow the link to Albert Malik's profile to learn more about it. Captain America should be Jeff Mace, but it is also possible that it was already the Communist hunting fake "Steve Rogers". The "Master Judge of the Lower Depths" most likely was Pluto. The only problem with this story is that Charon seemingly broke his silence which would make Hercules in his 2005 title a liar which wouldn't be a big surprise.

Thanks to Per Degaton found the info for the Weird Tales appearance.

A Hyborian version of someone resembling Charon also appears on Conan the Barbarian#250. A skeletal ferryman transports others across the River of Darkness :

The use of a coin to pay the ferryman for a trip across the River of Darkness is obviously derived from the Greek/Roman Myth of paying Charon to ferry the dead across the River Styx. The Hyborian era (16, 000 - 8, 000 BC) obviously predates the Greek and Roman Civilization, but it makes sense for the Hyborian version to have simply continued into the later legend, especially given the location of the real River Styx (Stygia, which became Egypt) in the Hyborian Era, and its connection to the underworld's River of Darkness.

While it is conceivable that Charon predates most of the Titans and their progeny the Olympians, it is unsure if it is actually he or not.