Hi All,
When we used to tent it, we used to fill up the tropical box (105L esky) the night before full with water, then put a couple of frozen cordial bottles in and close the lid. It makes it so you are not putting cold ice etc into a hot esky the next morning. We used to get at least 2 more days out of the ice than mates of ours who had the exact same esky until they started doing it too. We also used to put extra frozen cordial bottles in for ice. Also, buy yourself a couple of $2 sun shade for the car and tape them to the esky. Works a treat for the ever moving sun! Sometimes you can't always keep it in the shade at all times.
Now that we have a camper trailer, we bought 3 x 80L Plastic Tubs with Lid & wheels from Kmart and removed the wheels from one side and left the other side on. This stops them from moving around on the carpet in the camper, but still makes it so we can easily get them in and out.