This is finally solved. There was a problem with my computer's ADB RSA key, so I simply had to delete the key file and rerun ADB and I Received the RSA Key Fingerprint window instantly on my G3.
For the full description of the problem look here:
I get to "* daemon started successfully *" then nothing. After a lot of troubleshooting I know it's because my phone won't allow access by my computer. I never receive the RSA Fingerprint window allowing my computer access to my phone. Here's what all I've tried:
-Put phone into Internet>Ethernet mode (and I've also tried Internet>Modem, MTP and Camera modes as well just to say I did).
-Enable Developer Options and enable USB Debugging.
-Installed the drivers linked in the ioroot page (I've also downloaded the drivers directly from LG - believe it or not ... it's the same file).
-Installed the Verizon Software Assistant from the phone after connecting to the computer.
-Updated my ADB version with the SDK Manager.
-Used different USB ports on my computer as well as two different USB cables (one of which came with the G3).
-Checked Device Manager, all is as it should be and no unrecognized devices.
When I ran the adb server without the ioroot batch file, typing "adb devices" would return my phone's serial followed by "offline." It did this until I updated ADB; then when typing "adb devices" it would return the serial followed by "unauthorized." I've tried all various methods and combinations of switching adb debugging on and off, switching developer options on and off, installing and uninstalling and reinstalling the LG drivers, unplugging and replugging the USB cable, power-cycling all devices including myself at night, doing these methods with long pauses in between (10 minutes to ensure I wasn't being impatient), scratching my head, drinking more coffee, switching to rum and swearing at all devices but nothing seems to make a difference.
What am I missing?
I've got the Verizon LG G3 in White (LG-VS985W)
Software version VS98510B
Windows laptop running Vista 32 bit (I know I know, "eeew Vista")
I was able to obtain root using a different computer, here's what I tried with my laptop after gaining root to get it and my G3 on speaking terms:
-Deleted the ADB_Keys file on the G3 (/data/misc/adb/adb_key): no change.
-Compared running Windows services between Vista and 8.1 and started services which were running on 8.1 but not vista: no change.
Here was the resolution:
ADB saves a key file in one of multiple places on a Windows computer, the first is in the location where adb.exe is (C:\android), the second is in the user's profile (C:\Users\*username*\.android), the third place is in the Windows system files (C:\Windows\System32\config\systemprofile\.android), the file is simply named "adbkey" with no extension. If there is no key file when ADB runs, it will generate one automatically.
Mine was located in my user folder (C:\Users\*username*\.android\). All I had to do was delete the adbkey file (there was also a file named "adbkey.pub" which I deleted as well), restart the adb server in command prompt (adb start-server) and plug my phone in. I instantly received the RSA Fingerprint Key window on my G3 allowing connection between the two devices. Then typing "adb devices" returned my phone's serial number followed by "device" showing it was available. I went back to the C:\Users\*username*\.android\ folder and sure enought there were new "adbkey" and "adbkey.pub" files.
Problem finally fixed!
Here are some VERY useful links which helped me come to this fix:
How ADB enables a secure connection
Reconstructing ADB's RSA key file