Even a drive to Maine is only 3500 mi, out of maybe 10,000 mi per year, so think of it like, "what problems to expect in 3 months of commuting". Even less severe since no stops, starts, sharp turns. In most cars, loss of electrical is the most common disabler. In the 1970's, you could run a long time on the battery alone, but not today w/ all the electrical demands. But, your diesel doesn't need electricity except for headlights. Next disabler is over-heating, but your cooling system sounds up to snuff. If you make it over the Rockies on a hot day, no concerns. Just budget for fuel. 3500 mi / 23 mpg * $2/gal = $304. My last one-way flight to the east coast was $150. Some M-B diesel guys scavenge for fuel as they go, filling w/ used motor oil or even peanut oil, but the IP may not appreciate that.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans