Best Coolers

The coolers are your refrigerator and freezer when you are on your trip. Prior to 1930, an "icebox" was an essential in every house. Get a decent one and it will work well and last for years! Plus, you can use it for tailgating at a football game, a scout camping trip, the 4th of July party, or if the power goes own and you need to store food out of the freezer.

BUT... you don't need to spend a fortune on one. Leave that to the yuppie Millennial next door.

THREE coolers

Yes, you need

One big one (55 quart) for meats and dairy (I like the Igloo 55 QT BMX cooler, which keeps food cold for 5 days without adding ice),
One small hard side for drinks (about $30 at Costco or Sam's Club, when they have them in stock) (I like the Arctic Zone Titan Deep Freeze Zipperless Hardbody Cooler, which I use all the time, in the armrest between either the front or rear seats) and
A cooler bag like those sold at Costco, Sam's Club and Trader Joes (less than $10 at Costco or Sam's) for temporary overflow, vegetables, fruit, etc.

What you need to know about Coolers.

For your main meat and dairy cooler:

Forget the overpriced brands. We all know that guy who has a Yeti and tells you how amazing it is. Yeah? $300 for a cooler? It better COOK dinner for me at that price. Folks, it just needs to keep food cold for several days. You can stop and buy more ice ($2 for 10 lb bag) just about anywhere (gas stations, QT, RaceTrack, Exxon, WaWa, 7-Eleven, WalMart, etc.) Coleman makes good ones in general.
But don't buy cheap crap either.
Forget the Styrofoam coolers and thin-walled "Playmate" coolers. They simply don't work and will make a mess.
Size - Yeah, yeah, size matters, but you can buy too big as well as too small. For a family of 4, 55 quarts is a good size. You can easily hold 5days of meats and key items
A key tip is if you want to bring milk, Bring one 1/2 gallon frozen when you leave, and the rest should be shelf stable UHT milk.
Look for essential features like::
- Drain plug - you will need to drain water from melted ice at least every other day, and trust me, you do NOT want to have to tip the cooler over. That never ends well.
- 5 day cooling insulation - the ones that claim to keep food cold for 5 days have enough insulation to do a good job!
- Handles or grips - You need a way to pick it up and move. Wheels are nice, but take up a lot of room, and since you just leave it the car for the entire duration of the trip, they're really not needed.
DO NOT open the meat/dairy cooler except for meals - Each time you open it, you let the heat in and the cold out. And you need meats and dairy to stay cold for safety!

My recommendations

I got an Igloo 55 QT BMX cooler, took it on a 2 week cross country trip in July, left it in the car, even on 95 F days and it keep food frozen the whole 2 weeks. I merely added about 7 to 10 lbs of ice (at $2per bag) every other day, and drained the water out every 2 days. To do that, I just opened the back of the SUV and opened the drain plug on the cooler so it drained out on the ground. When I last looked, it had over 5,000 reviews and more than 4.5 stars.

For drinks, Arctic Zone Titan Deep Freeze Zipperless Hardbody Cooler, but anything you like will work!

And an inexpensive (as I said earlier, less than $10 at Sam's Club or Costco, a Jumbo oversized bag cooler for non critical items, like fruit and veggies.