#1. Not considering finances. Thinking you can take 1 credit card
for fuel expenses, only to find that the card ends up getting denied after X amount of charges 1,500 miles from getting back home, thus calling and getting a friend to wire money to them after sleeping in their car 3 nights.
Travelers Checks are your friend.
#2 Not checking firearm laws for every state they intend to cross,
as to type allowed and ammo in car, gun locked in trunk. 3 days in jail, $800.00 pistol confiscation, fined, yet convicted, sentence suspended.
#3 Full service of vehicle, battery test, brake inspection. All
roadside break downs will cost more than a front and rear brake job at home.
#4 Adding water and food rations to vehicle encase of prolonged
road side sit due to #3
#5 Adding safety signaling devices to notify oncoming traffic of
broke down vehicle.
#6 lawn chairs/blankets to sit or lay on well away from vehicle
while waiting, to alleviate being injured in the event a cell phone talker hits the vehicle by crossing out of the lane.
#7 Buy towing and replacement rental car insurance for the
longevity of the trip.