Most appear to have drawn a poly line and then used the spatial info tool to figure out the length. I actually used the row formula tool to figure out the prior delivery point, then the distance tool to calculate the distance which I summed up for each trip.
One advantage of the poly line approach is that you can see which points are included. I was going circled trying to figure out if I needed to add a final return leg but it looks like 61 is that return leg in all cases.