* Before you mount a nice-looking cooler on your tongue, consider using a more conventional tongue box up there, instead. While several TnTTT members have used coolers there, they've been steel, retro-looking types, not a plastic one. If you use that one there, you'd probably be tempted to use it as a cooler, and the constant motion would affect its' performance (sloshing, bouncing motions). If not serving as a cooler, then it probably is smaller inside than a comparable-exterior-sized box of conventional types. A decent cooler needs to be utilized as a cooler!
* I tried using a substitute box on my first trips, before I got my present one. It was a spare Husky toolbox I had, and used it to move my AGM battery to the tongue, for weight purposes. It was a bit small, but it held the battery and a few items of gear, though it looked a little bit too tiny, and not proportional to the trailer, so it was a temporary thing, until I found a proper sized conventional box. A fellow TnTTT member (
Prem) located a box he thought would be right for me on Ebay, and pm'd me. At $100, it was worth a try, so I bought and installed it on a sliding platform on the tongue (with A-frame shaped outriggers for stability). It has worked great for many years now. A similar box is listed on Ebay now for $114
https://www.ebay.com/itm/29-Heavy-Duty-Aluminum-Tool-Box-Truck-Storage-Underbody-Truck-Trailer-Tongue-/382149070510, and on Amazon for $148
https://www.amazon.com/Aluminum-Trailer-Tongue-Underbody-Storage/dp/B072SVK62T/ref=sr_1_37?crid=X9N11O4NB73W&keywords=tongue+box+aluminum&qid=1557617889&s=gateway&sprefix=tongue+box%2Caps%2C190&sr=8-37.

- inexpensive aluminum tongue box.JPG (83.16 KiB) Viewed 1729 times
* Looks like a good cooler, and might be better used near your camp kitchen or transportable in your vehicle, without using the trailer. You can never have too many coolers (I use 4 presently)! and, you can never have too much storage (i.e. storage boxes, racks, tubes, etc), but that's another story.
small toolbox is my only storage at first
larger tongue box and racks and tubes and boxes, oh my!