Do you have room to put another one in your main bathroom. That should stop them going to the one at the end of the garden. But, knowing the stupid things my sims do when left alone, no guarantees. The really annoying one for me is: Sim is in kitchen, kids have gone to school and the place is a mess. She is moaning with disgust. The maid is due shortly, so I decide there is no point in her doing the cleaning and send her to the lounge, which has the very best sofa and lounge chairs available and loads of decoration elements. She picks up the book, then walks all the way back to sit and read in the filthy kitchen. She does this every time!