Would the path tend to be pointed to by the wire-side of the pitless tend to be a clue? (7:30 o'clock in the first picture) Mine is that way.Often one can just imagine a line between where the pipe exists the house and the well head. That will be the path where the pipe and wiring is most likely buried. If the pressure tank is not insside, it is most likely either next to the foundation or next to the well head.
In reply #13, the sketch indicates he thinks the water comes in around the corner from the well. But the straight line could be determined thinking the pipe may have been placed before the slab was poured.
With the frost line at maybe 40 inches, how deep would a pressure tank typically be buried? I know the thought is that the upper part of the pressure tank contains air, so it can be above the frost line. Maybe that tank could be probed for with a steel rod -- especially if the ground is soft from rain.
Marshallda, do you have a friend with a metal detector?