I am a huge checklist fan, coming from both the GTD mindset and the philosophy for the Checklist Manifesto and would highly recommend taking the Checklist approach when it comes to planning for the curveballs during road trips.
All-season Outdoor Backpack Checklist
Light back-packing food (trail mix, chocolates, energy/protein bars)
Bug-repellent – I keep a mild one for kids and Deet-based for adults
Disposable Rain Ponchos
Swiss Army Knife or equivalent
First-aid box with analgesic
Water-proof pouch for cellphone (a must have since I bricked my Pixel 2 in Everglades in this trip)
Hand sanitizer and extra masks (if there are still masking restrictions)
Small pack of soft tissues
Battery juice pack with charging cable
Small towel and spare change clothing
Good to haves:
Portable selfie stick
Water-proof Bluetooth speaker – I have used this in most careless way around beaches, pools, hot-tubs for many years with no complaints
Some pennies to throw in the wishing well
Road Trip Emergency Checklist
• Download local maps for your destination – I use Google Maps ‘Download offline feature for the same. The cell reception could be patchy especially if you are going for camping/wilderness resorts.
• Enable Location sharing between friends, to track your friends. Tracking people or cars could be very inefficient and tedious. I use Google Maps for the same and find it the most reliable.
• For outdoor parks, check the local guidance using nps.gov or similar websites.
• Keep extra food, water and warm clothes in the car.
• For nature trails, try to download the offline maps, by using AllTrails or similar applications. Losing your way during a trail could be very harrowing/frustrating experience. I have been using AllTrails Pro (which gives you ability to download offline maps) for many years now and would call it an indispensable tool. It helped me immensely in places such as the Endless Wall trail in WV, Cherokee Falls trail in TN, Lover’s Leap trail in AR, Wanatee Park trail in IA, Trail of the old Oaks in IL when I was looking for directions and there was no one to ask.
• Keep extra cash. Once when we were coming back from Pictured Rock, one of our friend’s car got pulled over by a cop and we had to shell out ~200$ cash for the ticket, otherwise we would have needed to make a court appearance in a remote county precinct. Luckily, we had extra cash.