I put a Show Chrome rack on my B so I could carry my stuff such as laptop, extra boots/shoes, etc. I have been riding since the early '60s and have learned to also bring certain things for my B such as oil, tools, etc. I also have learned that, on a long trip, you can guarantee rain. So, since I also ride snowmobiles, I take my waterproof snowmobile bag and cram in the stuff I can expect to use during the day. Then, I lash it to the back of the B by attaching it to my backrest bracket and to my rack. This makes a very secure attachment that is also water proof. It also detaches quickly so you can take it into your hotel room. I then put clothes and other niceties in my side bags. Having experienced every kind of weird event on a road trip I pack double underwear and other clothes that I might need in my side bags.

This works out good for me since I rarely have a passenger. If you routinely ride with a passenger, you're screwed on long trips.