Denver, South Park & Pacific by Mac Poor - first published by the Rocky Mountain RR Club in 1948,
and republished as a Memorial Edition in 1976 - has several maps in a pocket at the back of the book,
including a full system map of the DSP&P and also one of the Denver, Breckenridge & Leadville. If the
Memorial Edition is still in print, I would expect the Colorado Railroad Museum in Golden to have copies
for sale. IMHO, this book is a MUST HAVE for fans of the Colorado & Southern narrow gauge lines.
The Pictorial Supplement to DSP&P was published by the RMRRC in 1959; the DSP&P system map appears to be the same as the one mentioned above, but the DB&L (Georgianatown Loop-de-Loop) map is replaced by a map of the Ohio Creek Pass extension. I have no idea whether this book is still available; the original edition was limited to 5,000 copies ...