Steve, looks like you found a great spot. I loved exploring that area, lots of interesting history. Ended up spending a extra couple of days in the area than originally planned exploring & did spot a number of places that looked to be great for boon docking. In hindsight I wish I had stayed longer.
Re the creative ways folks have suggested for getting rid of human waste. Note that Arizona BML website reads " To further protect your public lands, campers must not dispose of any refuse, hazardous materials, sewage, or gray water, in any manner that would pollute the surrounding area. PACK IT OUT." BC Recreation Campsites also have a rule on their website is very simple "Do not empty your holding tank"
I am well aware that a good argument can be put forward in regards to human waste not falling into the "pollution" category and it will eventually go back to the earth. But I have to ask whats to gain by depositing your human waste or grey water on public lands? Whats the gain over just either taking your porta potty or bucket with you or draining off your black tank or grey tank into a portable tote, once every 4-5 days or so and when out exploring the area dumping at a gas station bathroom?
I am a long time kayaker going into remote places (sometimes by float plane) for extended periods of time and I get why at times it is necessary to dispose of human waste in an eco
responsible manner at times but I really struggle with why it would be necessary to do that when camping with a trailer and having a car to take it away in.
Yes the gas station or approved site to dump may well be out of the way but I personally feel the trip or just draining the waste into a separate portable container and holding until I leave is more than worth it if it means I am not leaving more than a foot print at my camping area. With the increasing number of people using remote lands for camping, its pretty hard to say that you are in fact the only party who ever goes into that spot in the course of a year. It you were able to tow your trailer into that area its a real good bet someone else has and will also. Some of us work hard at "Take nothing but pictures, leave nothing but footprints.” As a result I know I would not be thrilled to be exploring my camping area and stumbling across what some animal has decided to dig up at a disposal site and the bugs etc it attracts and knowing the party that did it actually had a car to pack it out in.