I don't think ballparking these is worth the effort. If DL collects YQ/YR, it comes straight off the relevant revenue fare. Search on ITA Matrix for the route being travelled (breaking it up by segments if necessary) in the proper class of service. Set the currency to USD and the sales city to somewhere in the US (LAX or ATL are my defaults). The YQ/YR reported there is the amount that will be collected. People need to take a little bit of initiative on their own, especially given the way that airlines change their pricing (including these surcharges).