Okay... After a few hours of digging, trial-n-error, and frustration, I sorta' have some things working w/ my Nest Thermostat. Still some work ahead, but here's what I've done to get this far:

As stated earlier, I started w/ this article (but jumped around stuff like Samba; not a big fan of it or M$ Windows, and I don't need it since I'm running everything at home on Linux, Mac, or iOS): http://www.makeuseof.com/tag/getting-started-openhab-home-automation-raspberry-pi/

Also the Phillips Hue example didn't do much for me, so jumped at that point to OpenHAB's wiki on Nest Bindings: https://github.com/openhab/openhab/wiki/Nest-Binding

Steps:

(Steps 2 & 3 take about 20 minutes by themselves.)

1. Fresh install of Rasbpian "Jessie" full version (includes Java stuff needed; OpenHAB is built on Java.)
2. Ensure RPi's firmware up-to-date:
   
   rpi-update
3. Ensure running latest software:
   
   sudo apt-get update -y
   sudo apt-get upgrade -y
4. Install OpenHAB runtime. (Not real keen on this since diverges from original project, but shortest path to proof of concept and all that; perhaps I'll rebuild from scratch once I get things working.)
   
   wget -qO - 'https://bintray.com/user/downloadSubjectPublicKey?username=openhab' | sudo apt-key add -
   apt-key add -
   echo "deb http://dl.bintray.com/openhab/apt-repo stable main" | sudo tee /etc/apt/sources.list.d/openhab.list
   sudo apt-get update
   sudo apt-get install openhab-runtime
   sudo update-rc.d openhab defaults
5. Correct ownership of files:
   
   sudo chown -hR openhab:openhab /etc/openhab
   sudo chown -hR openhab:openhab /usr/share/openhab
6. Start tracking log file in new terminal window:
   
   tail -f /var/log/openhab/openhab.log
7. Confirm OpenHAB is running and webpage is ready to work (just missing the guts, so expect error listing.)
   
   URL: http://raspberry.local:8080
   
8. Download the demo site form OpenHAB.org, unzip, move files to where belong, correct ownership:
   
   sudo cp -r configurations/ /etc/openhab
   sudo cp -r addons/ /usr/share/openhab
   sudo chown -hR openhab:openhab /etc/openhab
   sudo chown -hR openhab:openhab /usr/share/openhab
9. Confirm it works:
   
   URL: http://raspberry.local:8080/openhab.app?sitemap=demo
10. Now install Nest Binding Add-on (actually first downloaded latest stable from OpenHAB w/o thinking, then went back and grabbed from apt-get source added earlier in instructions):
    
    sudo apt-get install openhab-addon-binding-nest
    sudo chown -hR openhab:openhab /usr/share/openhab/addons
11. Copy openhab_default.cfg to openhab.cfg.
    
    cd /etc/openhab/
    sudo cp openhab_default.cfg openhab.cfg
12. Using the Nest-Binding directions, Convince Google to let you tinker w/ your own device:
    
    1. Register as a developer.
    2. Register your "product".
    3. Gather your nest:client_id and nest:client_secret codes.
    4. Use the Authorization URL to get your pin_code.
       
       
13. Edit open.cfg: uncomment out the three lines of code for the data you just gathered under the Nest section, and add said data to those lines.
14. Using Vim (sudo apt-get install vim -y) , copy code samples of nest.items and nest.sitemap from https://github.com/openhab/openhab/wiki/Nest-Binding and paste into new files w/ these names in their respective directories. Since I do not own the Smoke+CO alarm, left this extra code out. Also did the trick they used in copying existing icons to newly named representations for Nest controls.
    
    
15. Change names of thermostat and references to item to match what was registered already w/ Nest account. In other words, their demo uses "Dining Room" and "dining_room*"; if your thermostat is name, "Yo Mama", then either edit manually or use something like this:
    
    sed -i '/Dining Room/c\Yo Mama' /etc/openhab/items/nest.items
    sed -i '/dining_room/c\yo_mama' /etc/openhab/items/nest.items
    sed -i '/dining_room/c\yo_mama' /etc/openhab/sitemaps/nest.sitemap
    
    (I would still recommend cat/less your files out to double-check yourself when done.)
    
    
16. Test and tweak...

NOTES:

• The log files will catch regular errors about "rrd4j" and and some other stuff related to the demo files installed. Once comfortable w/ demo stuff, best to get it off RPi (or at least out of the directories driving OpenHAB.)
• When rebooting, will need to start OpenHAB via CLI cmd: sudo systemctl start openhab; will fix this to autostart once get the bugs worked out.
• Webpage requires manual refresh to see changes you've made by clicking buttons. From what I understand, the smartphone apps are more auto-refresh responsive.