So, here's the story:
After Gathering of Winds, the PCs decided to track down Ilthane's lair before going to magepoint. Through the use of find the path they managed to do just that, and so I had to dip into Prince of Redhand for a bit. While in the Alhaster area they noticed the Great Project being built. Afterwards, they traveled to magepoint and spoke with Tenser about Kuluth-Mar. The situation has since taken an unexpected turn, as they are more interested in Alhaster than Kululth-Mar. Their reasoning goes "Ilthane was in Alhaster, so there's probably people in the city who have a connection to the dragon and we need to find out what is going on there". Now, this has the potential to be pretty cool, but I'm wary of any plot problems that may arise from switching the order of PoRH and SoLS. Any advice/suggestions on how to make this work?
Allow it. Have most of the leads come up dead ends, but you can let the players run around for a while. Kullith-Mar is a big part of the campaign. However, if you can find a way to include all of the information required (And I mean all of it) in a separate adventure, I'd do it.
Another option would be trying to track down Balkarde. "That old wizard? He went to the southern jungles years ago. Didn't he George?"
"Ayup. That's what I thought."
Of course, you could always have Manzorian scry the party, then send a message to them. "What? Where are you? Yes I know about the great project. We need you to find out as much about the original as possible."