First I suggest you read this. It gives pretty good guidelines of what you should shoot for.
Texas A&M Incubation site
Then remember that those are guidelines, not absolute laws of nature. Guidelines are intended to improve your odds, they don’t come with guarantees. Even if you do everything exactly right you are not guaranteed a great hatch. If you violate some you are not guaranteed a total failure. The more you violate the guidelines the less your chances for a great hatch are, but those eggs are pretty tough. Just do the best you reasonably can and you will probably do OK.
Some people feel those guidelines are a bunch of hogwash and don’t make any difference. That’s not really the case. They don’t understand what the guidelines are supposed to do or who they are developed for. The people who hatch a lot of chicks, maybe 1,000,000 chicks a week in incubators that hold maybe 60,000 or even 120,000 eggs each have spent a lot of money studying what it takes to get a good hatch. I hatch maybe 40 chicks a year in an incubator. A 1% improvement is less than half a chick for me. For these big hatcheries a 1% improvement would be 10,000 chicks a week or over a half a million chicks a year. That’s noticeable for them but not for me. Some of these things will make less than 1% difference, but some may make a little more.
It’s not black or white either. Not all eggs are the same. It’s not that all eggs become dead at a certain temperature. The hatchability decreases differently for each egg. Something may kill one embryo but not damage the others. It’s not that all hatch or don’t hatch as much as it’s more likely that not quite as many hatch. And there is often a wide band of what is acceptable. The further you vary from the ideal the less likely you are to get a great hatch, but that does not mean you won’t get a good hatch if you vary. I hope I said that clearly. The guideline matter but don’t obsess over them. Just do the best you reasonably can. And realize that no incubator in the world can consistently beat a broody hen.
Since refrigerated eggs came up, let’s talk temperature. The ideal is somewhere around 55 degrees. The embryo is alive in that fertilized egg. It is basically always developing or it is dead. At 55 degrees the development is really slow. You can hold them a long time without the embryo dying or developing noticeably. The further you vary from 55 degrees the less ideal the conditions are. If it gets too warm, say around 80 degrees, that embryo starts developing fairly fast. It can get to the point it will hatch in an incubator really early or it may not be able to sustain life since it is fairly far from the ideal incubating temperature of around 100 degrees so it dies.
On the cold side, the colder it is the slower it develops. If it gets too cold it can die. That’s a function of how cold it gets, how long it is at that temperature, and how tough that embryo is. Not all refrigerators are the same temperature everywhere inside them or the thermostat may be set differently. A refrigerated egg in one place in one refrigerator may be at a dramatically different temperature than an egg in a different refrigerator. Some people that live in really warm climates don’t air condition their house. Their choice may be between storing eggs in too warm a place or refrigerating eggs. Many choose refrigeration and get really good hatches.
Something else that is a guideline you won’t read in there is that you need to try to store eggs at a stable temperature. Swings from warm to cool are not good either.
Now to your specific situation. I once transported 30 eggs from a local farm over some really rough country roads, just over a half hour away. I’m convinced I killed at least a third of them by not having them cushioned enough. That was a really disappointing hatch. So definitely cushion them as best you can.
Store them pointy side down. Especially with them getting jiggled some I think that is really important. You don’t want that air cell to move.
If they are fresh, I would not worry about turning them. That article mentions they don’t really need to be turned the first week anyway. If you want to when you stop for the night you can, but I’d worry a lot more about cushioning and maintaining a fairly constant temperature than turning them.
You have some challenges ahead of you but I think it is very doable. Good Luck!