**** IT WORKS ****
Now for the specifics.
1) Running vanilla Gateway/Node code except for frequency declaration.
2) one end is a Moteino (no hookup, circuit issues here)! This end ran NODE code
3) one end is a Genuine Arduino Mega2560. This end ran GATEWAY code.
4) circuit hookup as follows.
RFM69W pin --> Mega2560 Pin
NSS <-- D53 (SS) using voltage divider (see notes below)
SCK <-- D52 (SCK) using voltage divider
MISO --> D50 (MISO) straight thru
MOSI <-- D51 (MOSI) using voltage divider
DIO0 --> D2 (INT0) tried voltage divider, no worky
Notes on voltage divider...
I tried the 4.7K/10K divider and got nothing....
I tried the 1K/2.2K divider and got some joy. Mega2560/Gateway doesn't get the interrupt properly..
Moved to next level of testing..
Tried level shifter from Adafruit on ALL lines ---> MUCH joy works without issues
Moved back to voltage divider on ALL lines EXCEPT DIO0 (used level shifter here) --> MUCH joy, works without issues....
Conclusion: voltage divider works OK for everything except interrupt line. Need level shifter on interrupt!
Now that I've got it working... Time to break it