When we stay in one location for a month or more it make sense to me to set up the sewer line to drain itself naturally rather than having to walk it out by hand under a slide. I have very seldom found that the parks we stay in have any natural slope to the sewer opening for the hose. I know that you can build it up with wooden blocks or stones or cement blocks but I don't want to haul those items around. I have a slinky but it seems to blow over in the wind very easily.
Thanks to those that had constructive posts. JMHO