Not OP but I have essentially the same bike (Packa) with kid bars on the back. I throw a big Home Depot plastic storage crate into the bars, then 4 bags of groc

Not OP but I have essentially the same bike (Packa) with kid bars on the back. I throw a big Home Depot plastic storage crate into the bars, then 4 bags of groceries go into the crate. 6+ if you stack and bungee them. Plus another bag in the front basket. If the kids want to go to the store then the crate goes on the bike trailer.