OK, did more reading, although I don't have a complete grasp of this.  I ran
C:\btcrecover-master\extract-scripts>extract-bitcoincore-mkey.py c:\btcrecover-m
aster\wallet.dat
Partial Bitcoin Core encrypted master key, salt, iter_count, and crc in base64:
YmxxxxxxqaVIxxxxxxxx6PjjUxxxxxxh/Jaxxxxxx8x/GCitxxxxxxxxDxxxxxxx21

and got above long string
then ran:
C:\btcrecover-master>btcrecover.py --data-extract --passwordlist
Starting btcrecover 0.17.9 on Python 2.7.13 32-bit, 16-bit unicodes, 32-bit ints

Please enter the data from the extract script
> YmxxxxxxqaVIxxxxxxxx6PjjUxxxxxxh/Jaxxxxxx8x/GCitxxxxxxxxDxxxxxxx21
Please enter your password guesses, one per line (with no extra spaces)
Use exit() or Ctrl-Z plus Return to exit
password1
password2
password3

exit
Wallet difficulty: 61,696 SHA-512 iterations
Using 1 worker thread
5 of 7 [#################################--------------] 0:00:09, ETA:  0:00:03
Password found: 'xxxxxxxxxxxxxxxxxxxxxx'

How do I get the private key out of the script?  More reading ? Thanks for all your help.
Tried pywallet --dumpwallet on it again but was no help.
I think I have the answer bitcoin-tool ... but having trouble compiling it.