How many gallons is the grey water tank?
The grey water tank is a 5 gallon bucket that is easily removed for dumping.
If I'm looking at the pictures right...there are two sets of sinks....purpose?
There is 4 sinks all together. We took multiple pictures, it may look as more.
Are the shelves shown in the pictures included?
Yes, shelves are included. Both the standing shelves and the ones attached above sinks.
How much does it weight and what size hitch ball would I need?
I have not had it weighed. With equipment, and frig it adds about 600-700 lbs. the insulation and electrical only added about 100lbs from original weight. Guess is around 3000 lbs equipped.
2" ball