Selling them all at once would be the preferred situation? As a potential buyer this is how I decide. I look for the current market price for white oak. GPS Hardwood is selling 8/4 or two inch thick white oak top quality with minimal knots for 9.50 a board foot. I know this wood is free of bugs, moisture content is correct etc. There are no surprises or hidden defects in that lumber, straight and flat pieces. And I can "cherry pick" the boards I want.
When buying from an individual, that normally is not the case. They want to sell them as a lot, take the good with the bad so to speak. Therefore the price must reflect that the possibility of not having usable wood in the sale. So asking what a good price for the lumber would be is gamble on both ends.
So using your measurements 56 boards at 2 inches thick x 10 inches wide x 18 feet long = approximately 1680 board foot (if I did the math right)
As a buyer I would then examine the wood and make a decision on how much I think its worth to me per bf then multiply that by approximate board foot. I calculate the driving distance, loading, unloading storage. That is a lot of wood!
So those are my thoughts, as I said before I am interested in the wood, perhaps a group buy from other members is an option, I don't need that much white oak, but I want it. LOL