Advice Needed on value of Books

Hi:
I am looking for advice from this group. I am helping my father sell his collection of Railroad books. They are all in fantastic condition. Any suggestions on how to set a price for them? I am open to options (indiviually, groups, the entire lot, Ebay, forums, ???)
Thanks for your thoughts.
Brian
Title Author Date
01 Narrow Gauge Country Lind 1963
02 Rails to the High Country Lind 1961
03 The Durango & Silverton Narrow Gauge Railroad Royem 1995
04 Narrow Gauge Nostalgia (Limited 1st Edition) Turner 1965
05 Railroads Of Yosemite Valley Johnston 1963
06 Narrow Gauge in the Rockies Beebe & Clegg 1958
07 Unitah Railway Bender 1970
08 Steam Locomotives of the D&RGW Warner 1957
09 Colorado Annual – 1963 Colorado Rail Museum 1963
10 Colorado Annual – 1964 Colorado Rail Museum 1964
11 Colorado Annual – 1965 Colorado Rail Museum 1965
12 Colorado Annual – 1966 Colorado Rail Museum 1966
13 Colorado Annual – 1967 Colorado Rail Museum 1967
14 Colorado Annual – 1968 Colorado Rail Museum 1968
15 Colorado Rail Annual – 1969 Colorado Rail Museum 1969
16 Colorado Rail Annual – 1970 Colorado Rail Museum 1970
17 Tracking Ghost Railroads in Colorado Ormes 1975
18 Colorado Memories of the Narrow Gauge Circle Krause & Grenaud 1988
19 The Reo Grande Souther Railroad Crum 1961
20 The D&RG in the San Juan Crum ????
21 Cripple Creek Railroads Feitz 1968
22 Narrow Gauge to Silverton Hungerford ????
23 The Gilpin Tram Hollenbach 1958
24 Chili Line, Narrow Gauge to Sante Fe Gjeve 1969
25 Colorado Mountain Railroads – Vol 1 Lemassena 1963
26 Colorado Mountain Railroads – Vol 2 Lemassena 1964
27 Colorado Mountain Railroads – Vol 3 Lemassena 1965
28 Colorado Mountain Railroads – Vol 4 Lemassena 1966
29 Colorado Mountain Railroads – Vol 5 Lemassena 1968