I've toured: .1. with a BOB, .2. with a BOB and 2 panniers, .3. with two panniers, and .4. with four panniers. For me, all work well, depending on what I'm doing. I find that we have drifted towards two or four panniers. Initially we had only one set of panniers, but we gradually added set after set of Arkels so now have enough for the two of us and our two kids.

On a solo tour dragging a BOB and a bike and the gear up and down escalators/stairs is a big pain. Storing the bike can be tricky. Now that I 'know' how to pack the panniers, during a tour I soon end up knowing where every item is, so tend to leave everything in the bags and just pick things as I need them. Compartmentalize. Stability is not compromised. I might even save the weight of the actual trailer, though with four panniers, maybe not.

My two cents, anyway.

Buen Camino.

B