Always take a Exigent Cover, use it every night when on the road. But I never put the cover on a dirty bike, I clean the bike @ night before covering. Contrary to Haird who wants to use his time for other stuff, I just feel like every day is better if I leave out in the morning with me & the bike (or car/boat) clean. Just makes a day away that much better to me, Haird does not think so, but I do.
I have found that if you look most motels have a hose somewhere, for landscape or pool or something, and all rooms have a trash can (bucket). I carry sponge in zip-lock with a small travel size shampoo bottle filled with car wash soap and a micro-fiber drying towel, also in a zip-lock. I stuff all this in the exigent storage bag with the cover, takes very small space, just part of my travel deal. Takes a few minutes daily, but worth it to me.