First thing, look at the provided feedback.
Second, I'd completely redo everything past "The Wight vanished, and perhaps it still sleeps in one of the last of the undisturbed tombs."
Do not go into 'module' detail with such things as "If there is a ranger or someone with wilderness lore in the group, he or she will know that the spores of the fungus are highly dangerous" - that is somewhat game specific and is jarring in terminology compared to the lead in story.
Instead, since this is not a full length module, but an idea that others will flesh out to full detail, outline the major cool or interesting features of the tomb. Perhaps carry on the narrative somehow to describe the tomb in the same tone as the lead in text.
Third, clearly define which King is which. I assume King Arkon is the older king and Dora's father is the newer king. Say King Rurick is King Rurick a lot sooner then when metioning Rurick's tomb. I was orignally confused as to who was who.
Fourth, I can't help but think of Dora the Explorer when the princess name is Dora.