Well I actually found something that was borderline witchcraft, but it worked. Stumbled onto this around 1AM using - Google - to search for someone that'd done the same thing. Of course this is where I originally started, but all of them involved downloading Shareware and weren't quite getting me to the finish line.
This clever guy's little script http://www.elsewhere.org/journal/gmaptogpx/
creates a NotePad file that I could get BaseCamp to accept.
Here's what I did:
1. Created my Google Maps route exactly as I wanted. THEN, I went to the bookmark that the folks in the URL above tell you to make earlier (it's a script generator).
2. It creates this script of details of your route(s) to which you Select All (Ctrl A) then Copy (Ctrl C) then open NotePad and paste into (Ctrl V). Save that files as WhateverYouWant.GPX (instead of .TXT). BaseCamp needs it to have the .GPX file extension.
3. Now open BaseCamp. This is a free application from Garmin (replaces outdated MapSource I believe). From the File menu, select Import, and select the .GPX file you just created.
4. Your Google Maps route(s) should be in a Garmin-palatable format whereby you need just select them all as I did (see highlighted blue in lower-left of screen grab below) and right click and send them to your USB connected Garmin device. It will take a few moments (probably 10 seconds) for the data to get sent to your Garmin. In the upper left corner of the above screen grab when you're doing this you'll see a faint green progress bar.
5. Next, unplug your Garmin and (turn it on if necessary) you'll get a message of "New Data Found on GPS. Do you want to deal with it now?" Select yes, or later just go to Tools (icon in lower-right of main screen on GPS)and select User Data and select Import Data, then Routes, then select all your newly created Routes and Viola!
I hope this helps. I'm not crazy about it, but it did work for me.