Saw a plastic folding table with a built-in sink in Home Depot/Lowes/Menards (don't recall which one). Seems it would be easier, but probably not cheaper. I think it ran about $85. You'd still need to supply the hoses and bucket.
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10