When I'm on the road I tend to wear what I was wearing in the pub the other night, lightweight bush kit, which is either non-iron, or minimum iron and easy to wash and dry. I also carry a smart shirt and trousers in case I need them. Somebody on one of the forums that they do their washing using one of the blue plastic drums, filled with washing powder, water and their dirty washing. They lash the drum to their bike rack and the movement of the vehicle does their washing, so they only need to rinse and dry at the other end.
Your situation is slightly different as you are going to be on site a lot, but before buying a generator I would look at posts about these on here, as some are very noisy and you will get complaints. I think Maplins do a portable washing machine for caravans etc. You could do what a friend who lives in a static caravan does and turn up with washing powder, fabric conditioner and dirty washing when you visit friends.
PS, after a week on here you should know better than to mention that you wear uniform...don't feed their fantasies or you could cause a lot of coronaries. x