I’ve been doing a lot of research on adding insulation into the various parts of our home’s basement (house is from the 1920s).  We are in climate zone 5–mountain west/Northern Nevada.  No humidity, and fairly dry summers (occasional summer storms), and winters are generally dry with a few feet of snow per year.  While our HVAC bills are not insane, I’m always looking for ways to be more efficient.  Our floors do remain cold in the winter.  Here’s some basic facts of the home layout: 

* The house is single level, with a basement under the entire length.  Part of the basement is fully dug out with a concrete floor, and has been finished with walls and a door to a utility room and a crawl space separated by a half/pony wall. 
* The finished portion is not sealed off from the crawl space, but it is separated via drywall/doors.  It is conditioned with HVAC vents.
* The crawl portion is conditioned indirectly via the ductwork hanging (see photo here: https://pasteboard.co/nDesq0yymccR.jpg), and also spill over air from the door gaps/etc from the finished portion. * The crawl portion ~36″ higher than the floor of the finished portion, comprised of dirt foundation.
* The basement walls appear to be some sort of concrete/blocks, followed by brick which makes up the exterior of the house.  You can also see the outside of the house in a photo here: https://pasteboard.co/npVuaRrRGXuj.jpg   At the top of the windows, you see where the exterior brick starts–this is the rim joist.  Interior pic of the crawl showing the rim joist: https://pasteboard.co/5845emTFkzaw.jpg
* We have had some water intrusion into the basement, but the only identified areas were in the finished portion, coming up via a floor drain.  Nothing active/identified in the crawl portion…in one of the pictures it looks like there was a leak at some point in time, but definitely not active. 

I have learned that insulating the rim joists and exposed wall surfaces in the basement can help create a better conditioned basement which will help with the main floor heat retention.  I have also learned that putting up foam board or even spray foam and insulating brick rim joists where brick is the primary structural element for the walls is a bad idea due to moisture entrapment. 

My questions:
* Given that I cannot access the entire basement at this point (because much of it is finished), is it worth the risk of moisture damage on the brick by insulating the rim joists on the front crawl portion? 
* If I leave the rim joists alone, what about putting up foam board insulation against the concrete exposed walls between the dirt and the sill plate?  Will that make enough of a difference if I cannot do the brick rim joists?

One thought I had is to just hit the rim joist edges with spray foam, but leave the foam board out of the equation to allow brick to breathe.  That might seal up some air gaps.  Overall, I’m just trying to assess if this is worth the time/money/effort, or if it’s better to just live with how it is. 

I have a couple of pics linked…please let me know if I’m not being clear.  Thanks so much in advance!