Both waste tank contents do indeed stink to high heaven. We haul ours in the lower storage bay. After it is used the last time we clean with heavy duty cleaner & bleach, allow to air dry and load it up. At the campground (we do have to use if for both tanks while at our favorite state park) we keep it under the coach (tie it down if its windy). And before we leave we give it another thorough cleaning.
You can put them on the ladder but we'd prefer to not have it out there in the wind just in case we need it and many time we don't so having it clean and dry in the lower bay works best for us.
When full, need to be dump, I agree...use a hook intended for the matter and hook it to a hitch and tow it to the dump station.