Help/advice for non-user data backups between system images

Layout:
c: o/s, "Users" folders on c:, but user data redirected as much as possible to d: (partition on SSD)
d: user data (partition on SSD)
z: in-box temp backups (laptops: partition on SSD, desktops: spinner)

external backup drive(s)

Once setup is "stable", (includes all planned prog installs, tweaks and user data folder stubs), a "c:" system image is taken using bootable flashdrive version of WD Acronis. Additional program installs are rare after this point, so new "c:" images will be infrequent, maybe only every 6 months. If there are program installs/updates between the planned "c:" images, a new image will be created or at least the install/update will be documented as missing from the last image.

User data is stored on d:, not in "Documents", "Music", "Pictures", etc. and will be backed up separately on a frequent basis. Home Groups/Libraries are not used. What I need to determine what other "stuff" needs to be backed up so that I can restore a "c:" image to a new drive, add the user data, run Windows Update and be ready to work.

"Stuff" I know about:

All Users Start Menu - copy folder to external drive, maybe weekly? Anything else in ProgramData?
User profiles - copy username folder(s) to external drive, maybe weekly? "Copy" the proper tool? FWIW, have Teracopy installed.
User (web) Favorites, mail - "mirror" to in-box temp backup daily using scheduled FreeFileSync? Copy to external drive, maybe weekly.
Registry - not sure how to do this. Brink's posts lead me to believe System Restore Points are the only/best way to back this up. SSD tweaks seem to suggest avoiding System Restore Points. And I want to be able to back this up to an external drive. Is there's another tool that could be run from the scheduler or a bat file to backup the likely meaningful user-modified entries like Start Menu Pins, Auto-Correct, etc? Confused if ERUNT is Win7 usable.

Trying to set this up so not much tech knowledge is needed to run it; hopefully just a combo of scheduled tasks and "click this shortcut" bats. What am I missing? Bad techniques? I only want to use free tools.

Registry is only an issue if you have updated it by installing an app or done a system tweak affecting it since you took the last image. The key to simplicity is keeping user data on a different drive and backing that up separately, as you've mentioned. Since there are are only a few steps to good "ready to go" imaging - once you've organized your system and data - using bats or scheduled tasks only adds to complexity and possible error. Using a simple checklist while performing the imaging/restore steps is all you need, if that.
The Programdata folder shouldn't be an issue for permanently installed apps. That data usually doesn't change after the app is installed, though I have one game that uses it for saved games. You really have to know where each app stores data, no way around that, but it's not hard to know.
The Users folder is another matter, and apps often put data there.
Doing "ready to go" restores really boils down to attention to detail in your initial data organization, and knowing which apps are storing data on the system drive, and where.
But every app I have that is data driven has a facility to backup the data elsewhere. So it's just a case of restoring it after the system restore.
Anything that can be directed to a non-system drive should be, but always keep in mind that apps and registry must be kept in synch. I do that by always imaging apps and registry together, meaning all are on the system drive. Games are an exception, but they aren't permanent.
If you're comfortable with imaging/restores one "easy" way to find what can be lost is to at some point after your first "stable" image - maybe a few weeks - do all your precautionary moving of data, take a new image, then restore your first "stable" image. Move back the "precautionary" data. See how your system looks after running it through the normal paces. If you find you're missing something, you can restore the latest image.
Then add what you neglected to move to your checklist.

Thanks for taking the time to reply, Victor S. I'm mostly trying to make sure I've done a decent analysis on "non user-data" backup needs. Not really too much a problem for my computers since I know what I've done & when I need to re-image. But I'm setting up a new laptop for a friend who is not techie and has a history of not doing backups. She knows better, but things happen and I end up doing the "fix". At least I've made a believer out of her for her own user-data. Anyhow, folder/file Security (permission attributes) of C:\User\username contents is an area that I'm worried about; is a simple "copy" good enough? As I understand, the Start Menu "pinned" settings are only stored in the registry. Still checking if there are others of note like AutoCorrect stuff that are worth exporting. Aiming for a "if the laptop has to be restored from a backup image, you'll be able to recover the latest this and that but anything else will be gone. If that's not good enough, do more frequent image backups <g>".

Sounds like you have a good handle on it. I've found that people just won't do what you want them to do anyway, as far as system imaging goes. So keeping the data safely backed up is the big deal.
If you get that worked out with your friend, and take that "stable" system image, you've accomplished a lot. Then if a restore is needed you're still way ahead of 90% of people, even if your friend has to do some tweaking. I see now why you were trying to automate some of it, but don't worry about that.
Your friend won't do it anyway.

I know that I've "got it all" with my backups while building my systems; I do full backups with WD Acronis of the entire partitioned SSD then restore it to another unpartitioned SSD & boot that SSD as a test. Good thought, though, whs.

As far as I can determine, Erunt is not documented to be updated to Win7, so I'm skipping that - but it was a fine program. At this point, I think I'll just try to backup a couple of selected parts of the registry with command line reg. Doubt that I'll do the whole registry 'cause I fear restoring it fully would create a mismatch of registry to a "restored" system. Of course, I guess I *could* do selected restores if needed. Guess it'll depend on time/space usage and just "how much is it worth?" effort is involved to avoid doing a WD Acronis partition backup.

FWIW, I don't install WD Acronis since it only offers full partition backups & feel it'd be safer/easier to just do it from a bootable flashdrive. IMHO, it's not worth the overhead to install it. I bailed on buying Acronis (that offers more features) several years ago when the new version couldn't restore a backup made by the previous version. For various reasons, I avoid the native Win7 backup.

Thanks for the offer, whs, but WD Acronis is doing what I need, so don't really see a need to switch at this point. I have seen that Macrium is highly-rated "pay" product.

Off-topic: I've no experience with Skydrive, but have seen it mentioned by several other posters on other forums who think it is pretty good. Any gotchas?

Thanks for the Skydrive tips. Have had an MS account for many years and see a Skydrive when I log in; just have never tried it. Haven't had a need for online storage or too-big-for-email transfers since the days of "Xdrive" (or was it "Zdrive") from many, many moons ago.