And yeah, I often like imagining the legend of the Dovahkin as it would be told in later generations. And 90% of it would likely be dismissed as patently impossible by scholars
Personally, the Dovahkin's tomb should be designed along the levels of the Tomb of Horrors. Because when a man collects so much loot over his life, and has so many other dungeons to draw from in terms of comparison and experience, there had better be some fine protection on that place.
First, one must approach the necropolis, passing through lands infamously frequented by werewolves and Dremora, where the wind carries whispers of madness and corruption. Some say these fiends haunt the moors in hatred of the Dovahkin, doing all they can to prevent another from ever rising to such heights as might challenge even them. Others whisper that perhaps they come to worship in their own right, that the Dovahkin might have been the greatest of monsters in his own right. That he made pacts with the daedra, for how else can one man wield such incredible power?
Then comes the outer limits of the great, dead city, the hall of craftsmen. Here one may find forges and enchanting tables, alchemy labs and groves of plants that may be found nowhere else in quite such profusion. In great leather-bound books, a prospective craftsman can find hints of techniques that shall make him the greatest of his age, recipes for the most potent of salves and instructions on how to bind the strength of the dragons themselves into your weapons. The Grey-mane clan makes a pilgrimage here every year, as do prospective students of the College, and it is traditional for each to leave a sample of their finest work in tribute.
Then come the catacombs of night, where the fiercest torch seems to flicker and dim, and all is shrouded in endless shadows. Monsters lurk in the endless gloom, perhaps Falmer or Draugr, perhaps worse. They do not attack, provided one is brave enough to face the darkness and press onwards, though none who flinch and turn in fear ever survive to exit the place again. The thieves guild merely laughs at such tales, crediting the legends of monsters in the dark to nothing more than some truly ingenious traps, and yet... and yet, none have ever attempted to rob the place, despite the wealth of ages that must be contained within.
Next, one passes through the Arcanum of the Arch-Mage, for none can deny that the Dovahkin was a potent sorcerer. Over time, successive mages of note have also been buried here, and the air thrums with the power of the wards that they have left. To step off the path is to be annihilated instantly by a surge of elemental power... unless one comes as student, with naught more than the desire for knowledge in their heart. Then, one might learn great secrets, but who exactly provides them is not something one publically reveals. The Mages have always been a tight-lipped bunch.
Finally, one reaches the inner sanctum. There is but one entrance, and to reach it you must pass through the Hall of Stories. The skeletal heads of scores of great dragons line the path, and beneath each is inscribed their name, all slain by the master of the tomb. Between the tributes, the walls bear the story of the Dragonborn, who fought with the World-Eater at the gates of Sovngarde itself to save all of Nirn from its terrible hunger. One cannot pass through the doors at the end without knowing the password in the Dragon tongue, and only the great wyrms themselves know that. To obtain it from them is a quest in its own right.
The catacombs within hold the resting places of the Housecarls, each a legend in their own right. They were buried with their war-gear, weapons of great might and armor to turn aside the fiercest of blows, and their guardianship is eternal. None may pass through without earning their approval, and any who try are reputed to be met by the full might of Sovngarde for their crimes. This part of pure conjecture, for none have ever returned who would try such a thing.
And beyond, there lies the Dragonborn himself. He sits enthroned amid the piled wealth of an era, and on the curved wall at his back are inscribed the great Words of Power, which none save he might ever truly understand. The Masks of the Dragon-Priests are mounted all around, their unified stares fixed on the entrance, and even centuries later one can feel their malevolence. Legend tells that should the world ever be truly threatened once more, then the Dragonborn will know, and rise from his throne. He will take up arms and armor once more, and accompanied by the legions of the Honoured Dead he shall stride once more into battle, the ground itself trembling underfoot.
But such a thing would be impossible, of course.
(And... Now I want to run a game based on this. The Tomb of the Dovahkin.)