Yeah, if you leave them idling then it should still sling fluid and lube stuff up, but it'd be quite the waste of fuel.
I'd pull the rear DS just for safety's sake. Since it's not a slip yoke it's not like it's any big deal. I'm not sure how the internals of a transfer case work though, so it may be a viable option to tow them in neutral.
Id still pull the DS. (once again)