I have plans to do the same, I am soon building a large gazebo with outdoor kitchen and will even have a 2pc bath, as it is not far from my septic tank (20 feet) it will be easy to tie in, and the driveway runs past the back of that location, so I will extend the trunk out the back and put in a 3x3 concrete pad slopped to the drain and a hose bib on the back of the gazebo, no more waiting in a long line up at the dump station to empty out a half tank, just dump when I get home, or do a good tank cleaning more often with no need to rush so not to hold up the line. even back yard camping, or using it as a guest house won't be an issue with the washroom.