Carol used a 20-ounce insulated coffee cup for the whole trip, and it wouldn't fit in the door pocket, so most of the time it was traveling between her knees. After she toppled it a couple of times daily for six weeks, Barney did a little engineering with corrugated cardboard and racer's tape to rig up this under dash "Grapes of Wrath" cup holder. And the navigator's desk is still hanging in there nicely as well.