If you have an outside shower don't forget to drain those lines too. Easy to over look when you are concentrating on the inside of the TT. 2 gals are probably enough but not a bad idea to get a third just in case.
2011 Jayflight 23FB G2
2003 Chevy 1500 4x4
Wife Peggy and 2 Beagles and a rescue Cocker Spaniel
2007 Yamaha Grizzly 400 ATV and Yamaha 2000 watt Genny
Me/retired insurance claims and DW/retired RN.
"If the women don't find you handsome, they should at least find you handy."-Red Green