Greg:
Ken Jessen wrote a small booklet on the GW. It only cost $2.50. I got mine at Caboose Hobby Shop. Don't know if it is still available, but I know Ken and might be able to spring a copy if you are interested. It is very brief, but is a good intro if you do not know much about the line. I have another GW book, but it is all about the diesel days.
Although it is diesel these days, the GW is still an interesting line as they use motive power from the 50s (GP7s and 9s and ex-SP SD9s). They even use their business car now and then to haul potential shippers around the line.