In the scene where Hilary and Trevor are sitting in front of the sofa eating and Jazz shows up, the bowl of popcorn behind them on the sofa is full, in the next shot it is half empty and then goes to full again.
After Uncle Phil, Will and Carlton leave for the trip, the impression is given that the camping equipment is secured to the luggage rack on the vehicle. Yet, when they exit the vehicle after it runs out of gas, all are shocked to see that there is no camping equipment secured on top of the luggage rack. It is very possible that when they first got into the vehicle before leaving, they would have seen that there was no camping equipment on the car to begin with. It then seems odd for them to be shocked to see no equipment on the car, since it is implied that they would have first seen it on the vehicle at home before leaving.