From what I can recall at least, we don't have many current active members in the Rockies region. There used to be a member on here, Hecklebone, who lived in Denver and had a Pinzgauer TD that he did extensive work on. You may see his posts if you have read about other Pinzgauer projects. Tragically he passed away some years ago.
As far as D24T "guru" - Most of these engines that remain on the road are maintained by their enthusiast owners as a hobby, so there is not much room in market for professional mechanics to make money off them, after the investment in the tools etc. As a result it's not the type of thing where any given city will contain a guru versed in them who can be hired for repair work, although such folks are out there.
If you are looking to get it in the hands of someone with specific experience, your best option is probably going to be shipping it to either Anders in Washington State or Tom Bryant in Maine. It may sound crazy to do that rather than find someone closer, but it will get your rig running right with no further question marks, so it may be worth it to you.
Or another possible option that may be a little closer would be Jason Douglas, the original founder of this forum who to the best of my memory now runs a VW specialty shop in St Louis area and of course knows the D24T engine well.
Or, persuade one of them to come visit you in the Front Range.
Tom as I recall has done things like that before.