Let me start off by saying that I am an old-house-hugger. Congrats on buying an old house and garage. You have a good looking and structurally sound garage of the era. I would try to avoid making changes that are not reversible. Your local historic preservation officer may have some suggestions.
I agree that water is seeping though the rear concrete block wall. Sealing the outside of the blocks below grade plus adding a French drain are good suggestions. Looks like your gutters are in good shape and carrying roof water away from the foundation.
You could probably lower the top sash of the rear window and install a fan like vickraft suggested without removing that nice looking original double hung window. Soffit vents would allow air to enter without defacing the garage doors.
I would be wary of puncturing the roof. Any time you cut a hole in the roof for fans, skylights, etc., you are creating an opportunity for leaks, plus it detracts from the original look of the garage.
OLD HOUSE STUFF:
If you are near Louisville, stop by
Architectural Salvage, WD Inc (614 E. Broadway). It's a great architectural salvage company for parts for your new (old) house and garage. Also, subscribe to
"The Old House Journal". The
website is pretty good, too. This is not the same mag as "Old House Magazine".
