The book recommended by "Hillyard Harry" is an outstanding value for a hardcover at $40. It was published by the Museum of North Idaho, PO Box 812,Coeur d'Alene ID 83816-3448. Ph: (208) 664-3448
ISBN: 978-09723356-8-3. I got my copy at Sunset Jct Model Trains, 419 E Sprague Ave, Spokane WA 99202, Ph: (509) 838-2379.

Now, to answer some of your questions. The line from Spokane to Mt.Hope was abandoned in 1952. It crossed the Spokane River just east of the shops at Hamilton & Trent, went south along Erie St. under the NP (BNSF), past the Liberty Park "frequency changing station" (the large brick building at west side of Liberty park) and then turned east, climbing up out of the valley. The top of the hill was at "Pantops", a gravel quarry at the top of Carnahan hill, a few blocks east of Havana St. Part of this line is a public trail, but much of it has been absorbed into neighboring properties and is not accessible. Here is a link to some current pictures of the shops and the Liberty Park Frequency changing station:

2 hours at Napa St, Page 4

This posting started out as "2 hours at Napa St" and morphed into a 9 page view of what some of the historical railroad locations look like today. Page 4 has the two items referenced above.