Your drive is classic flight nurse! Made me chuckle. My experience is similar to yours (2.5 SICU/2.5 CTICU). It has likely prepared you for the great challenge ahead. I know you worked very hard to prepare for the interview and to be where you are. As one who has just been through the process, I would suggest taking a break from all of the study and just relax! Spend time with friends and family and enjoy the accomplishment. Showing up rested will serve you well.
If you are anything like me, those words are hard to hear. If you must do something, I would get a copy of your "Standards". Eventually, you will need to know these inside and out. My plan before orientation started was to get to know how the standards were organized, so I could find what I needed quickly. Take one standard per day and read it through. Simple familiarity is a good goal.
You will soon be on information overload. There will probably be days where you wonder what you have signed up for. Be teachable, you are not expected to know how to be a flight nurse. Trust the process and lean on your preceptors and partners. Developing relationships with these people will be your greatest asset, along with your hard work.
My orientation was tough as the standard is high, but it should be! All the best in your new adventure!