Long Driving rather than flying or taking a train can often be more convenient .. Maximum output with some simple thoughts...
Ensure you plan for What Ifs while you are on your road trip.
What will you do if your car breaks down? Have you got suitable roadside assistance for your destination? Will your vehicle hire company provide roadside assistance?
What will you do if you have a car accident? Do you have suitable car insurance or travel insurance for your destination? Have you purchased insurance which will reduce your hire car excess?
If you have a problem in a remote area how will you communicate? Will you have mobile phone coverage on your planned route, or is it a major road with a lot of traffic who should be able to help you? Should you take additional communications equipment such as a satellite phone, a two way radio or an EPIRB?
Have you got a current first aid kit in your car and do you know how to use it?
Should you pack some additional bottled water and food in case of break down or traffic stoppages, particularly if you are travelling in remote areas and the weather will be hot?
If you will be travelling in a very cold environment do you have appropriate safety gear?