I have heard that some folks solve this problem by boon-docking exclusively at Wal-Mart and simply dump at midnight in the parking lot, storm drain, or landscaping.
Some people are just disgusting, aren't they?!
I think the simplest solution for me is to pull up stakes, and drag the 5er to a dump station. We can generally go a couple weeks between dumps, and are usually ready for a change in scenery anyway.