Yes, extra fuel would be good.
In my travels on many occasions I'd use another 5 gallons to get to a fuel stop. On one occasion needed 10 extra to make it to the next gas station (Out in Nevada I think it was). I carried 15 extra gallons, never needed the third can but sure glad to have it on hand.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-