How to carry more stuff on Term Quick Haul?

I have a Quick Haul with a seat and storm box on the back for my kid and a milk crate in front of my handlebars. Looking for best options to be able to transport my kid but more stuff - sports gear, his small bike or scooter, etc. It gets full quickly. I know this bike is a short tail and part of the appeal is it’s smaller size. But wondering if there are good options to increase the gear I can carry