For me it's several minutes' walking between the showers and my office, so I carry my toiletries and towel with me (along with my change of clothes) on the bike. I have a small brush, hair gel (small tube), deodorant, shampoo (travel size) and soap. Because I don't want to carry a wet bar of soap with me, I just leave a bar of soap in the shower (no one messes with it), but carry a new bar with me just in case.