Well, I love the investigations made by Pelgrane Press. I'd like to adapt some of them within non-gumshoe campaigns.
Here is what i'll do :
For non investigative things:
Replace them with your roleplaying game elements (replace characters, creatures, scenery, and so on).
For investigative things :
Before starting the game, try to know which PCs will come to play.
For each clue of the investigation, decide (and keep note) of who could find it without doing anything more than being themselves. How to decide ? Look at who those characters are, what are their backstories, what's written on their character sheet, anything that could convince you. (Could you do this on the fly ? Yes, of course. But being prepared may save time.)
During the game session :
Give each characters the same number of "investigative points".
They'll use it to gain benefits (which means anything that is not a core clue) according to their character.
As they are not linked to specific "investigative skills", you may not need to give them many.