Absolutely no reason to idle a diesel for a long period of time in the morning unless there's heavy frost on the window! I always back my truck into a space at a motel and if the lot slopes away from the building, I'll even coast the truck away from the building before starting up the engine. If not, I'll start it up, wait for the oil pressure to come up to the operating range and then gently drive it away from the building. I'll do the same thing at campgrounds. Of course, this is for my Fords that don't have air brakes.
As for idling after pulling, an EGT of 350 degrees F or lower won't result in coking of the turbo bearings and I've found that if I'm towing at speed on the Interstate, exit for fuel at a fuel stop, idling the engine for about 1 minute will almost always drop the EGT to 350.
