I've used a lot of different setups. basicly, combining a yak with backrollers is possible, you can haul allot of stuff, in my example the needs for 2 persons on one trip.
Usually I use or a set of backrollers (4 ) for me and a set of 2+2 for my wife, or my bob yak for smaller trips. For trips with the Brompton or fuel ex I use a set of handlebar/sadle bags.
When my wife cant ride with her bags I take the yak as an extra platform.
What's a backroller?