Interesting points about best glide speed and best endurance speed. I tend to mix the two up when teaching PFL's using words like 'Carb heat hot (cos most likely cause is ice), then trim for best glide speed to buy you some time to think while you consider wind and look for field.' Checks and Mayday call then secondary - fly the aeroplane first.
Thinking about it, 'Trim for best glide speed to buy you some time to think' is wrong. I should be saying 'best endurance speed'.
Presumably in a real life situation, the two speeds are likely to be within a knot or two of each other anyway. The main point is not to allow height to disappear as you descend at 100+ knots, or try to hold nose up with elevator (ie not trim) and run the risk of stalling while you're distracted with looking for a field, doing checks, making RT call, etc. Best glide is usually faster than best endurance, it's usually a familiar speed (about the same as normal approach speed), and in everything I've instructed on equates to pretty much the S+L 'picture', so it just 'feels' safe.
On several (demo) PFLs I've chopped the throttle on myself at less than 1000' AGL on the go-around from a student's PFL attempt and it's no harder (and often easier) then doing the same at 3000'+, assuming you're not over a city, water, forest etc. 'There's a field', into wind, full flap, mixture lean, swear over the radio with the word Mayday for good measure and drive the thing in. Worry about why it stopped once you're safely on the ground.
As for wind direction, I teach the 'Which runway did I take off from and was there a x-wind and if so from which side?' technique as a rough guide to surface wind.
Incidentally, on a recent tower visit, a military transit had an RT fail and appeared as a flashing 7600 next to the secondary return. On that particular radar set up, I was told that a 7700 squawk would flash in the same way.