Since so much of the Crystal Desert region, while "well known" to the residents, is still "here there be dragons" territory to the players, how about a small team creating landscapes and challenges in these areas. Access can be as difficult as the team can create, requiring players to not only KNOW the "right questions" to ask about access, but also knowing WHO to ask!! Some of these areas, like the Domain of Istan, or the Sandswept Isles, can easily? be filled in, needing only the "special" knowledge needed to "find" the access point--------a location known to but a few of the area's residents. Various "vacuous" clues can be strewn throughout the entirety of the desert (no reason to make this an EASY task, after all), and success can be added to the "Explorer" achievement. Since there doesn't "appear" to be any reason to return to the desert for more "dragon slaying", this would be a "nice" interlude between story chapters--------AND allow the maps of this region to be "filled in". "Scavenger's Causeway", on the other hand, can be an "invigorating" challenge for the more "intrepid" adventurers!!.
In conjunction with this, I note that there has always been an inaccessible transfer point from the Northern side of Brisban Wildlands to an unknown (possibly the Woodland Cascades?) area that is intriguing to most of us---------though it does tend to be ignored!!