As Byron said, with self-contained, there comes more problems:-
The added weight
of a water heater, the extra propane
, to fire it up, extra water, gray tanks, black tanks, dumping sewage.
Oh, how I hate that !!! Most 13' have a place to store a porta potti. I would much rather contend with a self-contained porta potti, or even one of the plastic-bag-kitty-litter toilets, than mess with a nasty sewer hose, and having to find somewhere to store the nasty thing !!
The shower is going to weigh a lot more, deprive you of storage.
There are several options for bathing:
Some folks just make do with a 'bucket bath', 'PTA bath'
for the ladies, until they can use the showers at a CG, Flying J, or wherever.
Some use the Coleman Battery-Powered Shower from WalMart, heat water on stove, and it pumps it up, and has a Spray shower head. ($25)
Some use the Zodi type portable water heaters, which run on a $2.50 canister of propane
, and 4 'D' batteries (usually about $60 on Ebay.)
Some use the Coleman type solar
showers, the sun heats water in big black bag that has a shower nozzle on it. Some Privacy Cabanas, like Duckworks Boatbuilders Stansport, have the supports in the top to hold the solar
bags of hot water. Some cabanas don't.
Most folks like to have a screen room/tent, (under $40 WalMart), by their door, and can curtain off a portion of it for private needs.