Spoiler (click to reveal)
So, my first Dunwich Legacy campaign (which involved Ashcan and Daisy) recently came to an end with them both being killed and the world being devoured as a result of failing Where Doom Awaits. Like many people I was initially struggling with how I can play LITAS despite this outcome and have it feature as part of my campaign narrative. Then it occurred to me... Stubborn Detective was Ashcan's random weakness during the campaign, and (in addition to other appearances during the campaign) he actually showed up during our climb up Sentinel Hill in WDA. When deciding how to play LITAS, I decided that the stubborn detective was actually Roland Banks, and he was sucked into the portal at the end of WDA. So whilst the world was devoured, it was on to a solo Roland play through of LITAS to determine his fate (it wasn't pretty).
So it turns out Roland was just following Ashcan and Daisy during the campaign to try and help them, but Ashcan (on the run from the law and panicking at the repeated sightings of the stubborn detective) kept knocking him out before he could explain his intentions. Perfect way to wrap up the story!