First, the hunter who died needs to make his Cult Lore (Odayla) roll to even know of this quest. It shouldn't be too big a secret because presumably Odaylan hunters have come back from the dead and said, "Dead? Nah, I was just sleeping" a few times in the past.
I'd say this HeroQuest has 7 stations: One for each day it takes the soul to reach Daka Fal's court. First station is obviously the River Styx. You pass into the land of the dead. I like Nightwood. That should be next. Of course, you've got your one unexpected station. And the court itself. That leaves three stations of the GM's imagining and of course Nightwood, for the PC to come up with what he needs to succeed in proving he is really just sleeping. The key is what did Odayla do? That can vary by locale, but is something the questor would know if he knows the myth. Remember, you can't take it with you, so if the answer is as simple as release an air elemental to claim you still breath (perhaps a disorder rune to augment your deceit roll here) then the questor needs to find the air elemental along the way. Which probably makes that "proof" you're not dead a rather difficult one to obtain in the underworld. On the other hand, if you're in Nightwood and you meet Trickster, you might persuade him to steal an air elemental from a certain storm god who stumbles into the Nightwood on his LBQ.
But you get my point, the journey to the Hall of Judgement becomes the heroquest to get out of Hell, seeking what is needed along the way. You can role play each day that passes after the hunters death as a station while the rest of the players continue on. "So today we do travel to blah, blah, blah, by the way, your hunter passes over the River Styx."
I would go this route with proving you're not dead: The Odaylan changes into a bear and points out that "Death is eternal and the dead cannot change, therefore I am not dead." this fits with his runes and his powers. It also means that if the questor does not have the rune points to change himself, he will need to find access to them on the quest itself. That would be something that reinforces the myth of Odayla the Bear. So your myth should allow the questor to gain one time use of Transofrm self or the other bear shapeshifting spells.
Better yet: In the Nightwood Odayla meets a bear, hunts to find it food, helps it defend its lair and when the bear goes into hibernation the spirit of the bear tells the Odaylan he can call on him. Then, at the Halls of the Dead, the Odaylan "awakens the bear" transforming into a bear and awakening the spirit of the bear.