The way that the BDR's are created it take into account fuel stops. Unless you drive a vehicle that has a small tank and gets really bad mileage, you should have no issues doing the sections with no extra fuel. Each section is +/- 100 miles. Most are less than 100 miles.
I completed the WABDR last year, it was awesome. I have done the lower sections several times, but only end to end once.
I completed the WABDR last year, it was awesome. I have done the lower sections several times, but only end to end once.

