I, however, did not find an easy fix.  After spending all day (i.e., over 10 hours) trying to muddle through commands I don't really understand, I read that the solution is in fact to reformat your harddrive (http://ubuntuforums.org/showthread.php?t=2218362).  Given this, I finally gave up worrying that fiddling with parts I don't understand by doing things I can't even pronounce is going to do even more damage to my machine than is done by making it utterly unbootable.

Released from care by knowing I'll probably have to start from scratch anyway, I start doing things nearly randomly, and may have added grub to every partition aliong the way.  Continuing this strategy with the options in boot-repair, I stumble upon a combination of chosen options that lets me boot.  I have no idea if I now (still?) have "a misconfigured system;" all I know is that after hours of trying random things after hours of having exhausted trying posted things, it finally works again.

For other's sake, I got it to work by using the general steps given here:
http://iambusychangingtheworld.blogspot.com/2014/03/error-symbol-grubtermhighlightcolor-not.html
with these these particulars (no idea what really mattered, so just giving it all):

=======================================

Boot-Repair Options
----------------------------

Advanced Settings:
Main options
- reinstall grub
- use standard efi
- backup and rename windows efi
- hid boot menu

GRUB options
- secure boot
- purge grub before reinstall
- did NOT upgrade grub to most recent version

GRUB location
- changed to windows (via sda5) [I think this was the critical point, but I really have no idea--I could have recited something from the Necronomicon and had as much faithin what I was donig]
- ata disk support

Output from boot-repair:
----------------------------------

Boot successfully repaired.

Please write on a paper the following URL:
http://paste.ubuntu.com/7341950/

In case you still experience boot problem, indicate this URL to:
<email address hidden> or to your favorite support forum.

You can now reboot your computer.
Please do not forget to make your BIOS boot on sda (2000GB) disk!

You may want to retry after deactivating the [Backup and rename Windows EFI files] option.

=======================================

With this, it rebooted to Windows fine.  To reboot to Ubuntu, had to go to Advanced Ubutnu Setup in grub and choose an old kernel (3.11.0-18-generic); it won't work if I try a newer kernel.

Please understand that I very sincerely appreciate the hard, selfless work that went and continues to go into the creation of Ubuntu and related products.  But please also understand that if you want people to share your work, you can't expect them to share your expertise.

There are those who love to tinker with their cars, playing with the cylinder timings, oil mixture, whatever.  But like many end users, I have places to go and things to do.  I use Ubuntu because, ideologically, I'm very for open source--but ahead of even strong ideological convictions are real-world obligations.  If I can't reliably put my key in the ignition and go, then, yeah, f*** this.  Spend all the time you want navel-gazing about Unity, Amazon, and the exact hermeneutics of bugs.  None of that matters to the likes of me if it isn't a rock-solid system that works.