Chuck; If you are having a lot of rain, I would tarp the roof or use clear plastic to seal off any open areas, top, roof, and sides. This will give you light to work, keep the wind and rain out, and keep your lumber dry and warp free. Trades and finishing contractors don't like to work on structures unless they are weather tight. Sooner or later you are going the have to install a wind and vaper barrier anyway, be it Tywrap or plastic. Don't forget, when you trench to run your power out there to include the cable TV, telephone, and intercom to the house wires also. And if you have time, install a rope and pully system so you can have lunch and a cold beer delivered without having to stop work and run to the house. As for the bathroom setup, a 5 gallon pail with an old toilet seat and some handy wipes should work. Don't forget the air freshner !!! I have a few other suggestions for you, but I don't think you want to start over, so I will keep an eye on your progress and see if I can save you some unforseen problems later on. Jim S