I carry 2 spare fuel filters and 2 gallons of clear kerosene along for those instances of b5-20 pumps and no other choices. If you haven't been burning bio diesel and you put it in, expect trouble. Thus: extra filters and some hot fuel to get it going.
And regarding the pricing at major truck stops, it is higher than smaller venues. But commercial discounts are significant enough that commercial users save more at the truck stops. I typically get 30-50 cents a gallon off the pump price.
Here, Pilot is $3.35 and Murphy is $2.90. Both have the B5-B20 sticker on the pump. I go walking in to Pilot with my Good Sam discount card and they say that I will get a whopping nickle off the price.