First, thank you all for your thoughts.
I talked with Cummings, and they told me the following, so I thought I pass it on to all of you:
Cummins recommends cranking your engine and letting it run for up to ten minutes at least once a month. This will circulate all your fluids sufficiently. Letting your engine idle for more than ten minutes at a time is not recommended as it can cause twice the wear on internal parts compared to driving at regular highway speeds, which can increase maintenance costs and shorten the life of the engine.
Again, thank you, Ed