Here's an idea I thought I'd share with others on playing Hessaret's Treasure in Glorantha. I ran this adventure with my Glorantha group with the following adjustments:
I slowed down the adventure's opening pace. It would take many days, even a week between events that happened over the first few days.
I set the adventure in Pavis.
Hessaret's Treasure became Jaldon's Treasure.
It was run concurrently with the events of Griselda's Great Chart Caper.
Gim Gim the Grim, the Pavis Temple, the Lhankor Mhy, the Lunar authorities, everyone is sold half of a map in advance by Griselda, ostensibly to "authenticate" the validity of her claim to have a map that leads to the fabled treasure of Jaldon Goldentooth. This leads the PCs to believe that she has the other half of the map, when in fact, her map has nothing at all to do with the PCs map. I never came out and said, but I led the players to believe that this chart that each thief ring had a part of, originally came from Herbi. Meanwhile, Gim Gim, the Lunar authorities, etc. come to the same false conclusions. Word gets out that the PCs might actually have the other half of the map or know its whereabouts. Ambushes ensure, skullduggery, intrigue as all sides seek to find Griselda and/or the PCs and/or one of the other two thief groups said to have half of a possible map. All of which causes everyone to go underground. Much confusion ensues. Having upped the bidding for the other half of her map, Griselda produces herr half of the map at the same time that the PCs finally unite the two thief groups with both halves of their map. By this point they may have discovered that Griselda isn't selling a map that has anything to do with their map. Or maybe no one has an authentic map. Maybe she's made different maps for everyone?
The PCs finally go on the adventure. They get to the final spot and just like everybody who was swindled by Griselda, they find nothing there. Until.....
Unknown to everyone, the final location of the treasure actually exists in a little known vanishing area in Prax. It is only visible each day for a few moments right at dawn when everyone can catch a glimpse of the Garden. When the PCs get there, it is near dusk. They find nothing. They believe they too were tricked. They camp out. Dawn breaks the next morning. At that moment they can see the hill and enter the area where Jaldon's "treasure" is hidden. Once entered, the players cannot exit until dawn the next day. Again, they do not know this.
This last little bit gives it a little flair like the movie The Mummy, where the lost city in the desert can only be glimpsed at that perfect moment.
After the PCs return from the adventure, at some point later Griselda returns and there's the big scene at the end of the Great Chart Caper. The PCs can make of that what they will.