Thanks for the code example for displaying the address of a data value.
I bought a Arduino Due with 16x more memory than the Arduino Uno and tried my program with so called "library stack problems" on the DUE.
The effort introduced a lot more uncertainties but the bottom line is the SD.open() function call consistently works when running a demo program and consistently fails when running with a several libraries.
Lack of program memory is not the single problem causing my application failure.
Here is the attack I am going to try:
I am going to isolate the SD library activity, the RTC (real time clock) activity, and the String() activity each into a separate function().
For the resulting function() calls, I am going to put "address of..." telltale number data at the top and the bottom of each function().
Then I have separated the function() s so they do not fight and I can see of one of them is failing to return with the stack in good order.