I started travelling with a huge 65l backpack. Way to much fort hat trip.
With the help of a good friend I didshed a lot of stuff and changed my luggage to a small seasack, which I put on my bike and a Chrome Industries Kharkiv bag. This bag includes a pocket for a 15“ laptop and a few more small pockets. One great feauture ist he exterior helmet storage, which can be folded down to safe space. The bag is actually made for commuting, but for me it is a perfect fit for light travelling.