I haven't been on here in a while and will update my profile soon but, after using my trailer for 5 years I could not imagine not having the toilet and shower in the trailer mostly because I use it in warmer months and a shower at night feels great and being able to use the toilet at any time.
I shoot it sporting clays shoots and if I am done early I will load up and then take a shower so my drive home is comfortable not hot and sweaty. and it I need to use the restroom I have my own.
I use the portable toilet that is permanent but I put in a pvc drain so I just flush it out with a water hose. my grey water just runs on the ground because I boondock almost every time. if I am parked in public on pavement I use the oil catch pans you buy at walmart they work great and hold 5 gallons.
My experience is to have the generator as far away from the trailer as you can get because of fumes and sound, I have a honda 2000 with a extended run tank.
I haul a golf cart so I leave them on the cart so I just drive it around to the front of the truck and unload it and reload it the same way, recently I have been thinking about buying a larger champion generator that has a wireless remote start so I can start and shut it off without having to go outside. I just need to think about a way to secure in in the back of my truck bed , but you would still need to un hook the trailer and pull the truck as far away from the trailer as you have cord.
and no question the window AC is a must, I started with the portable and went to a 8000btu and I am sure you can get by with less but I love cold AC and it gets cold in no time even in the summer in GA and FL.