I have done the full ISW deal in an RV for 8 out of the last 9 years, traveling from AZ. Skipped last year because of Covid. There is not really a "central" camping area from which to travel the full circuit. All of the tracks have at least dry camping facilities. Terre Haute and Lawrenceburg have limited hookups. Seems that every year they get close to capacity quicker than the year before, but I have never yet been unable to find a space.