We have a 2002 Coachmen Cross Country Elite with 54000 miles. Never had any electrical trouble with the coach on 5000 mile trip this summer. I start it every couple of weeks just to keep the "juices...
As a side note, do not start your coach unless you can drive at least 25 highway miles. This advice is from Cummins, Caterpillar, etc.
You will add moisture to the crankcase if you don't get the OIL (not just coolant) up to operating temperature. That can not be done on a diesel unless operated under a load.