Almost every motel I've stayed in will provide you with rags if you ask. I use these only to wipe down the seat and clean the windshield. My panniers are packed with maybe four or five coloured rags. These get used and thrown away as necessary. Sometimes I wash them at motels. I keep a small ShamWow in a sealed bag for my visor. Other than that, rain works well on a trip.
On a 2008 trip to visit Dog River in Saskatchewan, I discovered when stopped at the provincial Welcome Centre that my boots, the engine guards, the panniers, and of course the fairing, were covered in gigantic, squashed, grasshoppers. Hit rain on the second last day of the trip. The bike looked great when I arrived home.
Of course in 2007 after sliding out on a Colorado gravel road, I found a self-serve car wash and gently hosed and rinsed down the bike and had another client do the same to me.
Have a blast on your trip next week!