I don't have any external cargo storage on my SUV or my Wife's crossover. I have been looking at a bike rack to hang the double stroller off of. That will free up 7 or 8 cubic feet inside the cargo area without killing my gas mileage. I'm not ready to eat the cost of a hitch receiver and cargo box or a sport trailer for just the occasional use.

Getting back to the original question... Dedicated storage/moving crates, totes, or boxes for packing efficiency.