A navigation app can estimate when you will arrive. It cannot tell you whether the driver will still feel alert at that hour, whether everyone can wait until the next town for a restroom, or whether a fuel stop will be convenient with the trailer you are towing. Those details belong in the plan before departure.
Look at the whole journey on a larger map first. Notice long gaps between towns, mountain sections and roads with few alternatives. An apparently small detour may involve a very different road. Check the relevant transportation agency for closures and restrictions instead of treating an automatically suggested shortcut as confirmation that the route is suitable.
Plan stops you can actually use
Choose a few likely places for fuel, food and rest. For an electric vehicle, check compatible charging locations and the information supplied by the network and vehicle manufacturer. Leave room for a charger being busy or unavailable. For any vehicle, avoid making the last available energy or fuel the basis of the schedule.
Think about access as well as distance. A stop on the opposite side of a divided highway, an underground garage with a height limit or a small parking lot may not work for your vehicle. If someone needs accessible facilities, look for specific information about the stop rather than assuming every service area has the same layout.
Mark an alternative for the longest stretch. It need not become a complicated itinerary with dozens of reservations. The useful question is where you could stop earlier if a child feels unwell, traffic costs an hour or the weather deteriorates. Save the important addresses offline and keep a simple written route with the travel documents.
Leave the arrival time flexible
Tell anyone expecting you that the estimate includes stops and can change. A promised arrival time can quietly become pressure to keep driving. NHTSA advises taking steps to avoid drowsy driving; feeling sleepy is a reason to stop safely, not a problem to solve by turning up the radio.
Divide driving only among people who are willing, licensed and comfortable with the vehicle and conditions. Switching to an exhausted passenger does not create a rested driver. If the journey cannot fit into a reasonable day, change the journey rather than trimming the breaks on paper.
On departure day, check conditions again. Once underway, let a passenger handle updates where possible, or pull over safely before changing the route. Keep the destination and overnight arrangements available without searching through messages. A good route plan makes it easier to stop and reconsider, including deciding that the remaining miles can wait until tomorrow.