In case anyone is interested, the app I have been working on with the Mega2560 has been ported to the Due with minimal hassles.
The biggest issue was re-wiring the serial tx/rx pins, with the shields stacked on top, one needs to bend the pins out to be able to get the jumpers in place. Wow, tough :).
The app on the Mega was getting more and more crowded and sluggish, lots going on and a fair chunk of data for the RTC. I do have more data than code :).
All looking good and things seem to be snappier with the Due. And I have LOTS of resources left :).
One note though, libraries for use with the Due can be a challenge to get worked out. One example was the adafruit sensor library for the DHT22 (what I am using), hoses the IR library send functions. I suspect that there are not a lot of people using the Due so libraries for some stuff is lagging.
Only one problem, the development unit seems to have had the internal mic die, can plug in an external mic and that works, no idea what this is all about yet, but not a big deal for the dev unit.
All in all pleased! Fun times :-)!