I used Google Earth and the ruler to measure the distance of each of the four legs of the flight to arrive at a total en route distance of 295 miles.
I did the same and came up with 241 nautical miles (256 statute). I suspect the difference is in our respective calculations of the launch and recovery points.
Using the more accurate ship's deck logs lat/long locations, I found the distance to be approximately ~290 statue miles. I also found that the hand-drawn paper map was innaccurate by as much as 5-10 miles. Also of interest is the ships bearing after leaving the launch point. You'll notice that the hand-drawn paper map 'draped' onto real-world coordinates is very skewed compared to the actual deck logs plotted lat/long locations - especially when they talk about coming with 15 miles of the island. By plotting the hourly locations of the deck logs, you can actually 'visualize' the ship coming to a halt for each of the recovery efforts. It is pretty impresive. I can post some GE files if you like?
The most interesting thing that I stumbled upon was a very predictable pattern regarding the distance and timing of the searches. If you calculate the entire linear distance flown plus the distance of three perimeters of each island/reef (3X circled passes), you come up with a very accurate elasped time matching the total time enroute. Using the plane's speed of 90kts (104 mph), that nearly matches the launch/recovery times with an accuracy of just few minutes. This 'formula' works not only for the McKean/Gardner/Carondelet circuit, but is also remarkably accurate for all the other searches as well.
I suspect that the SOP was to make 3 passes of each island then move on. Using this as a benchmark means that they likely spent around ~20 minutes making 3 passes of the ~12 mile perimeter of Gardner.
I'm working up a detailed re-analysis of the flight using the Colorado Deck Log, Lambrecht's article (it's not actually a "report") and Google Earth - a very handy tool I didn't have when I did the original analysis many years ago. When I'm done we'll post it as a research bulletin on the TIGHAR website.
I have some GE files to share if interested. Also, does TIGHAR have a professional version of GE ($500)? This allows animated movies and other goodies to be created.
Some comments from earlier discussions:
I found (from the reports and letters) that the fliers were able to spot much smaller (non-aircraft) items from the air. In particular, I found it interesting that they were able to identify loin cloths (or lack thereof) of the natives waving when arriving Hull, rock cairns at Phoenix, and huts amoungst the trees on other islands. Also surprising to read that the natives heard the planes coming upon arrival at Hull and had enough time to gather on rooftops. If the pilots could see such smaller items, they certainly would have had the same capability at Gardner. If the natives heard the planes coming, that would indicate that folks on the ground were able to identify approaching aircraft - most likely from the sounds of the WASPs (engines).
Regarding the usage of the word 'markers'....
I feel as though this term was used by the pilots to reference previous expeditions' attempts to 'mark' an island. Either with rock cairns, flags, poles, etc. Oftentimes, rock cairns are referred to as 'markers' in situations like this.